(Part 1 covers the history and design of the 335-series engines. Part 2 provides details on the specific variations of the 351C, 351M, 400 and Australian 351C and 302C).
The American auto industry was dominated by the high compression overhead valve V8 engine from the 1950s to the 1970s . Each of the Big Three, AMC and the Independents released numerous versions of these V8 engines from the late 1940s all the way until 1970. Although General Motors had more engine families than any of the other manufacturers, Ford was a close second. Considering the majority of Ford’s engines were shared between divisions, it is quite astonishing that between 1952 and 1970 Ford released eight different V8 engine designs. Ford’s last overhead valve V8 engine of this period was the 335-series engine, released for the 1970 model year as the 351 Cleveland, followed by the 400 in 1971 and the 351M in 1975.
Like On the Waterfront’s Terry Malloy, the 335-series “could have been a contender” had circumstances been different. It represented some of the Ford’s best engineering and design efforts, but it never saw its full potential. In On the Waterfront, Terry Malloy was a victim of his brother who convinced him to take a fall in a fight, while the 335-series engines were a victim of bad timing and a dramatic shift in the automobile industry. The 351C was at one time quite legendary, especially among Ford high performance enthusiasts, but as time has moved on its legendary mystique has been somewhat lost in the sands of time. Today most Ford enthusiasts default to the common small-block “Windsor” engines.
Although Ford had many engine families, by the 1967 model year it didn’t have anything in the increasingly popular mid-sized V8 displacement range. In mid-1966 Bill Gay was assigned to be the chief engineer of the Engine and Foundry Division. His first responsibilities were to enlarge the 289 to 302 ci and to develop a new mid-sized displacement version of the small-block Ford. Bill Gay chose George Stirrat to oversee the mid-sized engine project. Stirrat determined it was best to increase displacement of the small-block Ford by the lowest cost possible. With a 4” bore in a block with 4.380” bore spacing, cylinder size was already near the maximum. As a result, a stroke increase of ½” over the 302, from 3.0” to 3.5”, was determined to be the best solution. To accommodate this long stroke, a 1.28” block deck height increase was required and the crankshaft main journals were enlarged to 3” for increase strength.
This new engine, called the 351 (but actually displacing 352 ci), was to be produced in Windsor Engine plant #1, hence the eventual name, 351 Windsor. The 351W was added to the Ford line-up for the 1969 model year, and was offered in 2V (for 2-venturis of the 2-bbl carb) and 4V variations (for 4-venturis of the 4-bbl carb).
Early production forecasts had showed that the Windsor plant wouldn’t be able to keep up with demand. The decision was made to expand 351 production to Cleveland Engine Plant #2 and that these Cleveland built 351 engines would undergo a number design improvements. Some historical sources suggest that the 351W was a stop gap to hold Ford over until an all-new mid-sized engine could be developed. This may be why Ford decided that the 351s being produced at the Cleveland plant were to see design improvements.
In early 1968, Bill Gay assigned George Stirrat to head the 351 Cleveland project. Stirrat selected Joe Mucura to work with him. It was sometime during this time of the infancy of this project that upper management decreed this new midsize Cleveland built engine should have a minimum displacement of 335 cubic inches with room for expansion, which is how the engine series got its name.
Mucura and Stirrat had differing ideas on how to build the new engine. Each came up with their own design for the cylinder heads. Mucura’s design, dubbed the 335-M, had large free flowing ports and valves with canted valves, similar to the larger Ford 385-series engines. Stirrat’s design, dubbed 335-S, used cylinder head with inline valves, similar to the 351W, but with larger ports and valves. Of the two designs, Sales, Marketing and Product planning greatly preferred Mucura’s design. It was more innovative and seen as more appealing to the public since it had more high performance potential. Stirrat and Bill Gay were also impressed with Mucura’s design and so it was decided to go with Mucura’s design.
After this decision, Stirrat and Mucura were reassigned. Bill Gay continued to oversee the 335-series project. Gay had the additional objective to make engine assembly easier and to improve quality control. The intake manifold was redesigned to be dry, meaning no coolant flowed through it. This reduced intake manifold heat and potential coolant leaks. The complex timing cover of the 351W, which tended to be hard to seal, was also redesigned. The engineers extended the engine block casting to encase the timing chain. This would allow the timing chain cover to be simple and cheaper piece of flat steel. The block extension allowed for the coolant cross over to be incorporated in the engine block.
The engine itself continued to use the same 4.380” bore spacing of the Ford small block from which it evolved, however, the new design permitted a slightly lower deck height of 9.2” compared to the 351W’s 9.48” deck height. The engine’s lower end was a short skirt design like the Windsor engine, but the main bearing caps and bulkheads were enlarged and strengthened significantly. This stronger bottom end allowed the main bearing diameter to be reduced to 2.75” from 3” used on the 351 Windsor.
Interestingly, after Mucura left the 335-series project, he became involved in the Boss 302 engine project. He decided to take his poly-angle “Cleveland” head design with him and be used it on the Boss 302 engine. The Cleveland head design could be easily retrofitted to the 302, only requiring the coolant passages to be modified. So in essence, the public was able to get a “preview” of the upcoming 351C with the introduction of the Boss 302.
Regular production of the 351C began in July 1969, and the engine was introduced for the 1970 model year in Ford and Mercury cars. The 351C generally replaced the 351W (there were some exceptions) in the intermediate and the pony car lines. It was offered in two variations, the 351C-2V and 351C-4V. In comparing the 1969 351W to the 1970 351C, it appeared that the 351C was a lot of hype for not much return. Both 2V engines had the same 250 hp rating and the 300 hp 351C-4V was only 10 more horsepower than the 351W-4V. Performance tests of the times suggested the two engines performed very similarly. So what was the big deal about this engine? It was all in the state of the art cylinder head design. These heads gave the 351C significant power potential and arguably gave it the most power potential any V8 engine of its time.
Many V8 engines of the era, including Ford’s own Windsor engines, used a wedge combustion chamber. Ford went a different route with the 335-series engines, using a much shallower poly angle combustion chamber, with the valves canted both horizontally and longitudinally. Unlike the wedge combustion chamber, this type of chamber is very efficient and does not have stagnate pockets outside of the main combustion chamber that result in unburned fuel/air. The 335-series combustion chamber promotes excellent turbulence of the air fuel mixture which results in a highly efficient combustion process of the entire fuel/air mixture.
Ford hard started experimenting with poly angle combustion chambers in the early 1960’s and found that it produced a broad flat torque curve. It didn’t produce the highest peak horsepower, but it produced the highest average torque. Ford wasn’t the first to use this type of combustion chamber though. The 335-series combustion chamber was similar in design to Chrysler’s poly-spherical chamber.
Ford produced two versions of the 335-series combustion chambers. First was an open chamber head, which was a shallow open combustion chamber. The second head was the closed chamber, which is where the combustion chamber volume was reduced with small quench areas on either side of the valves. The broad shallow combustion chamber of the 335-series heads creates excellent turbulence and no part of the combustion chamber is shielded from the flame front. The quench area was only used to decrease the volume of the combustion chamber to increase the compression ratio – not to increase performance like when used with a wedge chamber.
It is a common misconception that the open chamber 335-series cylinder head with its lack of quench is more prone to detonation. This is the case with wedge combustion chambers, however, Ford engineers and other experienced 335-series engine experts both agree that the open chamber heads are no more prone to detonation than the closed chamber heads. This is again the result of the thermally efficient shallow combustion chambers used on both styles of heads. Each combustion chamber has its own advantages. The closed chambers have faster combustion at lower RPM compared to open chambers. This results in an increase in low RPM power, but there is no improvement to the mid to high RPM power. The open chambers’ valves are less shrouded, which improves low lift airflow, between .100” and .300” valve lift, in comparison to closed chamber heads. This improved airflow is seen throughout the entire RPM range.
The other excellent design feature of these heads was the poly angle valves. The valve train and valve layout was essentially the same as Ford’s 385-series engines and very similar to Chevrolet’s “porcupine” big block. The poly angle valve layout permitted the 351C to use much larger valves and ports than a typical engine in its size class. The intake and exhaust ports were designed for high flow and low restriction. By canting the intake valve towards the intake port and the exhaust valve towards the exhaust port, it allowed engineers to maximize the port airflow. This layout correspondingly increased the space for the valves allowing for the installation of very large valves.
Unlike the 351W that preceded it, the 351 Cleveland had unique cylinder heads for each carburetor variation. The 2-bbl engines used a “2V” head and the 4bbl engines used “4V” heads. The 2V heads had larger ports and valves than the 351W but the 4V had downright massive ports. They were the largest ports of any small displacement engine of the era and used huge 2.19”/1.71 intake/exhaust valves. With two port sizes and two combustion chamber designs, there were several variations of the 335-series heads.
As we’ve seen, the 335-series engine cylinder heads featured high performance oriented big canted valves, massive ports, and combustion chambers with excellent thermal efficiency. So what was the reason Ford made such a performance oriented head for production cars? At the time of the engine development, Ford was heavily involved in Motorsports. The engineers that designed this engine took all of their past experience learned from Fords Motorsports to design what they deemed to be the ultimate Ford performance engine. The 4V cylinder heads were designed to be a state of the art racing head that was tamed for production engines. The 4V heads were capable of producing 500 hp in NASCAR configurations, and even more power in Pro Stock racers. Even the more conservative 2V heads flowed very well, and could supply enough air to feed an engine with 400 hp.
To get an idea on how well these cylinder heads performed, compare them to another well-known performance cylinder head of the times. The Chevrolet small-block engine was known for its high revving nature and its free flowing heads. The “double hump” heads were for a long time considered the best production castings made by Chevrolet. While they flowed well, the 351C-4V heads flowed significantly better. In the chart below you can see that even non-performance 2V heads are pretty on par to the Chevrolet head, while the 4V head is far superior.
All the great engineering that went into this engine came at a cost. As a result other aspects of the engine were also re-engineered to save money. One area where Ford engineers identified cost savings was the oiling system. Unlike the Ford small-block family, which had three main oil galleries, the 335-series engines were reduced to two. This oiling system sent most of the oil to the cam bearings first and did not give priority to the main bearings on the engine. There were other engines that used similar oiling systems and under most circumstances that production engines would be operated, it was adequate.
The oil system had several design flaws that caused problems with this non-priority main oil system. The lifter bores had excessive clearances and too large ports which causes excess oil to leak out of the lifter bores. This reduced the amount of oil available to lubricate the crankshaft. The oil leaking around the lifters can also lead to oil cavitation from the lifter motion, which also can impede oil flow to the mains. Excess oil flowing to the valvetrain and camshaft bearings also reduced oil flow to the lower end bearings. All of these flaws can lead to lower end bearing wear and low oil pressure. High performance 351C variants were tuned to run at high RPM and that is when this oiling system could show weakness, in particular from the cavitation, resulting in oil starvation to the mains and potentially bearing failure. Due to the large variation in tolerances in these engines, many but not all of these engines suffered from these oiling system problems. Today, engine builders who specialize in 335 series engines have found various solutions to address the oil system and these engines can be made to be very reliable in high performance, high RPM applications.
All 335-series engines all used thin wall casting. This resulted in thinner than usual cylinder walls. Because of this, typically a .040” overbore is the maximum for any 335-series engines, although in some circumstances .060” overbore can be achieved if the block is checked first. In very high horsepower and racing applications, the cylinder walls may not be sufficiently strong. However, Ford cast stronger engine blocks with thicker cylinder walls for NASCAR racing, including one variant that had siamesed cylinders.
By the 1971 model year, Ford had almost fully phased the Ford FE engine out of its automobile line-up. While the 385-series replaced the larger FE iterations, Ford needed something to replace the 390 FE V8. So, it was decided that a larger 400 ci version of the 351C could fill that gap. Using the smaller 351C as the basis would result in a smaller and lighter engine than the 390 FE.
To create the 400, Ford had limited options. Since the 400 was to be based on the 351C, it shared the same 4.380” bore spacing. The 4” bore left little room for further expansion. So it was decided that the stroke would be increased to 4” to create the 400 (which actually displaced 402 ci). To accommodate this increased stroke, Ford had to increase the deck height by over 1” to 10.297”, which was very close to the 385-series deck height. This deck height increase permitted the use of longer connecting rods so the 400 could maintain the same rod-to-stroke ratio as the 351C. However, this also meant that there were less parts shared between the engines. It also resulted in the 400 being slightly taller, wider, and heavier than a 351C. For these reasons, many don’t include the 400 as part of the 351C family. The reality is that the 351C and 400 shares the same basic design and are obviously from the same family. Ford created the 400 from the 351C in the same fashion it created the 351W from the 302.
Interestingly, Chevrolet also created a 400 ci engine from its small block Chevrolet and encountered similar problems to Ford. The Chevrolet small block has a bore spacing of 4.40”, which is nearly identical to the Ford 351C. So there was little room for a bore increase. However, Chevrolet decided to increase the bore to 4.125” by using siamesed cylinders and then it only required a 3.75” stroke to make 400 ci. Even with the shorter stroke of 3.75”, it could not maintain the same rod-to-stroke ratio of the 350 without an increase to the deck height. So Chevrolet compromised the rod-to-stroke ratio, and used a shorter rod in the 400. This allowed for more part interchangeability in comparison to Ford’s 400.
To accommodate the longer 4” stroke, Ford strengthened the bottom end of the 400 with an increase in main bearing size to 3” in diameter. Ford also used a slightly larger piston pin, a unique three point motor mount (as opposed to two point mounts on the 351C) and the larger bell housing pattern of the 385-Series engines. These changes meant that along with the bigger engine block, the 400 used unique rods and pistons, pushrods, crankshaft and associated bearings/caps, intake manifold (due to the extra width), exhaust manifolds (due to the extra height), and engine mounts. The remainder of the engines parts were interchangeable with the 351C.
All Ford 400s were low-performance engines, and almost all had compromised engineering due to Ford’s attempts at trying to meet emissions standards. As such, the 400 has long been painted as a boat anchor smog engine, when it is entirely not the case. While there were no high performance variations, the engine has the same design benefits of the 351C, with the advantage of extra displacement. However, there are a number of drawbacks that have prevented it from being commonly used as a high performance engine.
Ford made one major design compromise to reduce the compression on this engine. The combination of flattop pistons and the same cylinder heads as the 351C-2V produced an unacceptably high compression ratio for regular fuel. So engineers simply increased the deck clearance (moved the piston further down into the cylinder at top-dead-center) to get it to a regular fuel friendly 9:1 compression. The end result was the excessive clearance, twice that of a 351C, and this reduced much of the cylinder heads excellent turbulence. This caused some stagnation in the combustion chamber and detonation was the result with all but mild tuning. This wonky deck clearance measurement stayed with the 400 throughout production.
Until recently, the only solution to correct this excessive clearance was by using custom-made pistons, or modifying 351C pistons to work with a 400 connecting rod. Today, the aftermarket offers pistons with proper deck clearances that also boost compression.
The high performance 4V heads can also be used on the 400, however there is no intake manifold that will fit the larger ports or exhaust manifolds designed to account for the additional deck height. There are aftermarket solutions to these problems, but they aren’t cheap.
As a result of these hurdles, the 400 has not been overly popular as a performance engine, and beyond the late 70s truck crowd, there is little interest in the engine. Nevertheless, those who have taken the time to build a 400 Ford can produce a very potent engine. It doesn’t have the same high RPM capability as a 351C, but has the advantage of a much more robust torque curve. In fact, the engine Builder John Kaase won several Engine Masters Competitions with the Ford 400, beating out traditional muscle car engines such as the Small-block Chevrolet, Ford Boss 429, and Ford FE 427.
The 351C was only in production for 5 years in the North American Market. It was discontinued after 1974 and was replaced by a tall deck 351M, which was a destroked 400. The 351M used the same block as the 400, meaning much more parts sharing occurred which saved costs.
In 1971, Ford of Australia began to produce the 351C in its Geelong plant, along with a small displacement short stroke variant displacing 302 cubic inches. Dubbed the 302C, it was a destroked 351C that shared the same bore and stoke as the 302 V8, but used 335-series engine architecture.
By the early 1980’s 335-series engine production ended in both countries. Like Terry Malloy, this engine had so much potential to be great, to be a legendary engine, but it just didn’t happen. Designed as a high performance engine, by 1971 the auto industry had started to make a drastic shift away from performance to focusing on meeting the ever tighten emission standard. This resulted in compromised engineering being applied to these engines almost immediately out of the gate, simply to allow Ford to meet emissions standards. During this time, Ford was also moving away from Motorsports, ending the need for investment into high performance engineering.
The 335-series engine did have brief moment in the sun with Ford enthusiasts as the 351C-4V, but eventually it would be surpassed by the Ford small-block that stayed in production longer and had far more aftermarket support. We saw a glimpse of this engine family’s greatness in the Boss 351, but ultimately most of the engines from this family were rather ordinary performers saddled with low compression and rudimentary emissions controls. Imagine judging the small block Chevy, or any other V8 of that era, only by its 1970’s variations? Stayed tuned for part two of this series, which will discuss the specific 335-series engine variations in more detail.
Great article, thank you! My experience with this engine was with a 1971 Cougar, which had the 351C 4 barrel mated to a 4 speed manual transmission. I found the car in a repo yard back in 1974. It had been towed rear axle down, in reverse gear, so the clutch was smoked. It was missing a few parts but still had the factory Hurst shifter with the T handle. Me being a naive 19 year old, I installed a new pressure plate and clutch, replaced the missing carburetor with a Motorcraft of unknown origin, and freshened the brakes etc. That car ran flawlessly for the 4 years I owned it; I sold it to a fellow that kept bugging me about it. Of all the cars I’ve had I think that I miss that one the most –
Thanks for this tutorial on one of the most confusing engine families in US automotive history. It is interesting that the Chevrolet 350 and the Chrysler 360 were designs that seemed to come about without confusion or drama and that stayed in production for eons. The Ford 351 was actually three different engines of wildly differing specs and capabilities.
That was the maddening thing with Ford engineering of that era. So much work went into the engine, with so little parts commonality shared with other engines. It was a little reminiscent of Chrysler’s early V8s that came in such a dizzying array of variations. And then the oiling compromise – those cost pressures lead to some interesting decisions to those of us with the luxury of hindsight.
Do you mean the Chrysler 340? I think the 360 was originally a truck engine that was pressed into car service when it became too difficult to get the performance-tuned 340 to meet emission regs. But for the time, the 360 ran okay, too.
The 360 was in cars in 1970 or 71, primarily the big C bodies.
No problem though with GM having four distinct 350s, 400s, and 3 455s, a 454 and 472/500…
Nicely done, Vince. I’ve always been fascinated by the myriad variants of Ford engines, and it’s interesting that Ford might have planned the Windsor as a stopgap. In reality, Ford needed the Windsor by 1966 at the latest, when it could have offered Ford an answer to the Chevy 327.
How can you consider this a confusing engine family when there is only 3 variants? 351C 351M and 400. It is simple to understand, JPC. Part 2 will probably make it much clearer.
I was using “engine family” in another way – in thinking of the “Ford 351”. One sticker on the air cleaner (or 2, with the 2V and 4V callouts) but three distinct engines with not much in common. Had they gone with true displacement and called it a 352 it would have added the 4th, bringing the old FE based version to the party.
The GM 350s of the 70s were confusing too, being four completely different designs. But those all came from legacy engines birthed by GM’s old Divisional structure. A structure that Ford was not burdened with.
Thinking of “engine family” more strictly, as in the 335 series, we get only 2 of the 3 351s. Both GM and Chrysler saw a lot of use out of their “mid displacement” engines, including police pursuit versions in their later years. But Ford never really got there with this one, tossing it aside and going back to the older Windsor design for the 351 that saw police duty for a time. At least that’s how I understand it.
Actually, the 351 C-Q-Code was listed in the police engine lineup thru the end.
The early brochure didn’t list power & torque for any engine, and I took the liberty of typing them in based on info I researched online. Maybe Vince can verify that these figures are correct. 255 SAE Net HP from 351 CID wasn’t too shabby in ’74.
A junkyard find of a ’74 base Torino 2-door cop car Q-Code, talk about a unicorn.
https://www.hotrod.com/articles/junkyard-find-ford-mustang-ssp-torino-police-interceptor/
I just tried posting a link to a junkyard find ’74 base Torino cop car 2-door Q-code, but it was flagged as spam. How can this be resolved?
Is it no longer possible to post links?
Thanks for letting us know — I restored the comment above. Unfortunately, the Spam Filter often flags comments that contain links — when that happens, if you leave a comment here saying that you had a comment trashed by the Filter, we’ll restore it as soon as possible.
I know it’s annoying, but it’s better than being swamped by spam.
As usual, Roger is on the money. Ford offered the Q-Code in police cars from 1972-74 in the intermediate cars only. It’d be the only way to get a Q-code in a 4-door (normally limited to 2-door cars).
Roger, your numbers are all good except for the torque on the 400. It was 330 lbs-ft @ 2000 RPM. I think you wrote in the 351-2V torque by accident. I also agree that 255 hp (net) from a 351 in 1974 was excellent. It was actually the most hp/ci of any V8 that year. I will touch on this in some more detail in part 2 of this article. That Q-code Torino you linked to is really rare. A Q-code but a 2-door police package car, wow.
Besides every GM division (excluding Cadillac) having their own 350, the same applied to the 400 CID engine (and the Chevy 400 was a small-block).
Frankly, I suspect it was all some sort of marketing ploy, with the size ‘350’ and ‘400’ simply sounding better than other displacements. In fact, I might go so far as to suggest that 400 may have been the only displacement used by each of the Big Three, maybe even at the same time. And, as one might expect, it was AMC who went with an oddball engine size, using 401 for their big engine.
Not only that, but all 4 divisions rounded to 350 Cid. The Pontiac was actually a 354 and the Olds was a 349, the other 2 were actually 350s
I always presumed that GM HQ planned the demise of Division-specific engines for awhile and the first step would have to be everyone coming together on a couple of common sizes. Once everyone had a 350 it would be easy to share among Divisions. Most folks probably wouldn’t notice – it would have been their mechanics.
That’s a logical theory. Not only the 350 and 400 engines, but the 455, as well. It actually played out with the big Oldsmobile ‘scandal’ and subsequent lawsuit in the seventies when, for the first time, GM started putting Chevy 350s into Oldsmobiles. It was pretty much the beginning of the end for division-specific engines:
“The case involved 50,000 purchasers of 1977 Oldsmobile Delta 88’s, Omegas and Custom Cruiser station wagons that were equipped with Chevrolet 350-cubic inch engines instead of the highly publicized Oldsmobile ”Rocket” 350-cubic inch engines.”
https://www.nytimes.com/1981/06/28/us/jury-orders-gm-to-pay-10000-in-switch-of-engines.html
I tend to think otherwise. There was already an edict in place from the 14th floor in 1963 that the midsize cars were not to exceed 330 CID. Which explains why the ’63 Tempest’s V8 was called a 326 instead of its actual 336 CID. And why the new small Olds V8 that replaced the 215 in 1964 had 330 CID.
After DeLorean busted through that with the ’64 GTO, the max for midsizers went was raised to 400 inches. Which explains the Buick GS 400, even though it had a 401 until 1967.
Then it was raised to 455 for 1970, in order to stay competitive with the big block intermediates from Chrysler and Ford.
There’s little doubt in my mind that the 14th floor also decided that 350 was going to be the new small V8 engine size too, in 1968. Olds, Buick, and Pontiac all slightly increased the size of their small V8s to “350” in ’68.
I do not think that GM was already planning a mass switch to universal engines across divisions in this time period. It was just a way for the divisions to not compete against each other with engines sizes. They competed in so many other ways, corporate wanted to keep a lid in this one key aspect.
I strongly suspect that the idea of using engines across divisions was essentially forced on them, initially in 1978 when Olds couldn’t meet the demand for 350 V8s. Once they crossed that line (and got busted for it), they figured they might as well play it safe and put in a disclaimer for all of them.
Actually, what really triggered it was the first energy crisis (’73-’74), when the demand for smaller cars and engines could not be met by the divisions. Hence the Buick V6 showed up in increasing other cars, and then the Iron Duke (and some others too). but I don’t think consumers were complaining about them, as well as the Ventura with its Chevy engines. But Olds 88 buyers were more demanding in that regard.
The second energy crisis finally killed much of what was left of this divisional engine structure. Of course GM couldn’t exactly have know these two energy crises were coming, especially back in ’67-’70. The old divisional structure with its unique engines was still solidly in place back then.
GM actually went the other way once engines were used across divisions. Hence there were 301, 305 and 307 V8s. And 262, 265 and 267 V8s. And the Olds 403. And 227 and 231 V6s. So that rather bolsters the argument that the “350/400/455” limits were used to keep the divisions in line, and not for future cross-divisional use.
However, starting in the early ’60s, it does seem like divisions were encouraged to “snap into line” to get more commonality with transmission bolt-up, flywheel/starter arrangements, mounting arrangements. Previously there was a lot more variety exercised.
Almost as if for “corporate” to acknowledge that eventually sharing would happen.
If there ever was an engine born at exactly the wrong time, the 351C is it. Just imagine if it hit the showroom in ’65 like the BBC…
Agree!
The 351C is like the polar opposite of the unlamented 1980 255 V8, which was a miserable engine that did nothing well, save meet emission requirements.
This was an interesting read, nicely done!
I think today’s Ford lineup is pretty convoluted as well. They have 6 engine options in the F-150, plus 2 more for the SuperDuty and another for the Ranger. That’s a lot of truck engines. And I believe all of them are new or significantly revised in the past 3 years.
And a big difference between 1969 and today is that cars and trucks (mostly) don’t share engines. Back then, car and truck engines were effectively one and the same, spreading out development costs.
Then again, Ford builds and sells millions of F-series, so I suppose they can afford all those development costs for engines that are strictly used in trucks.
Thank you for a most informative article. I learned a lot.
My one exposure with a Cleveland was a 351C that was supposedly a factory 4V engine that was swapped into a ’69 Cougar I had prior to my ownership. Granted, I didn’t know much about the engine’s history or what it came out of but it didn’t make a lot of power and its durability didn’t really impress me when it spun a bearing without warning while idling in traffic.
I remembering you mention this before Dan. I wonder if your engine was a victim of long term damage due to the oiling system, This seems to be the case especially for engines that have been flogged at high RPM frequently. FWIW, a lot of guys take a 2V engine, swap on a 4-bbl carb and intake and think it’s a 4V engine. So, it is quite possible to have had a 2V heads,
That said, even if you did have a legitimate 351-4V (say an early M-code with the high compression), they weren’t super strong out of the box. They were tuned so mildly by Ford, that while better than past engines, they didn’t run like a 340 Mopar. The 351-4V’s had tons of potential, and could be made to run with little work. The Aussies made the M-code 351-4V run much stronger with a little work, with the Falcon XY Phase III. In the States, the Boss 351 actually had a decent cam, with the high compression and carb that let it breath. It would run with the big dogs. I will get into more details on these engines in the second part of this article.
This is an excellent article, thanks for your research!
I do have to say, however, that the Boss 302/351 Cleveland “canted valve” design was nothing new or unique. Chevrolet first used it on its Mark II 427 big-block engine which debuted at Daytona International Raceway in February of 1963. By January of ’65 it was in regular production as the 396 Mark IV.
Thanks for the feedback, it’s much appreciated. You are entirely correct that Ford wasn’t the first to use the canted valves. I even mention that the layout was similar to the Big Block Chevy in the article. However, unlike the Chevrolet layout, the 335-series and the Boss 302 heads did not use a wedge combustion chamber. They used a shallow poly angle chamber.
In the what-if department, I often wondered how a 400 built to Q-Code specs would have performed.
Also, does this site no longer allow posting links?
I tried to post one to a Junkyard Find 1974 base Torino 2-door cop car-Q-Code.
Try 1 more time.
https://www.hotrod.com/articles/junkyard-find-ford-mustang-ssp-torino-police-interceptor/
IMO: The FE series engines were FoMoCo’s weak spot in the 1960’s.
I’ve owned several of the “335” family; always found them reliable and “Real World” pleasant engines.
Pity they didn’t arrive, perfected, earlier.
I knew a guy who worked a Ford parts counter back in the late sixties/early seventies. He once commented that the then-new 351W engine was always in for warranty work, while the 351C never was.
And it is a real puzzler why it took Ford so long to get a competitor for the Chevy 350 and Chrysler 340 into production. Usually, it was Chrysler that was late to the party but, in this case, it was Ford. I guess Ford management must have felt sales were good enough that engine development to match the competition was unnecessary. I can’t really blame them all that much. It was sort of the same over at Pontiac where the 389/400 in the best-selling GTO routinely got pasted by everyone else (save Ford products).
A 351C-4v in a ’67 Mustang would have made a world of difference. Instead, it got the boat-anchor 390, making the sharp 1967 Mustang one of the most disappointing musclecars of the era. Ironically, another Ford V8 that tends to get panned is the Cleveland-type Boss 302, a big-valve, high-rpm, free-breather hampered by its small displacement at low revs.
It took Ford unti 1970 to get it right with the 351C-4v, virtually too late to make any kind of impact in the performance market, and the type of engine ill-suited for emission standards just around the corner.
The Boss 302 existed for but one reason… to homologate it for Trans-Am racing. I’m not sure they were the best choice for the street-
The peak torque rating on one is actually slightly less than a garden-variety
302-2V, at a much higher RPM. Ford actually recognized this issue and reduced the intake valve size in ’70, from 2.23″ to 2.19″.
It was also put into Cougar Eliminators, where the Cougar’s extra weight made it even more unhappy, I would imagine.
I agree with you on all your points Roger. The one thing I will say though is that the Boss 302 was considerably less high strung and had better street manners than a 302 Chevy. Because of the free flowing heads, it didn’t need as much camshaft duration as the Chevy, and allowed the power band to be lower. Because of this, it was capable of very similar performance but with better street manners than a Z/28.
I always thought it was interesting that the Boss 302 got the biggest valves (2.23″ intake valves). I wondered if the 2.19″ valves were also implemented to save costs, since they were shared with the 351-4V. Both of those valves are actually too large for a 4″ bore. They worked okay with a NASCAR 4.080″ bore, but on a 4″ bore, you can actually get better flow out of 2.06″ valves (used on the 1973 and newer 351-CJs),due to less valve shrouding.
See this pic below, where you a modern LS7 cylinder head leaves some space to prevent valve shrouding. At the time, the engineers didn’t know this, but now this design is used in most modern designs:
It’s interesting that the Z/28 302 was a worse engine on the street than the Boss 302. None of the reviews mentioned it, and it’s the Boss 302 that gets the vitriol to this day. Maybe it was due to the creature comforts the Mustang offered by 1969. I vividly recall a Car and Driver article on the Boss 302 subtitled something like, “Tell car 32 that his stereo is too loud”.
As to the Chevy 302, someone once told me it was first created by hotrodders simply boring out the cylinder walls to 4.00″; the rodders called it a 301. But it only worked on some older 283 blocks that had enough webbing to tolerate that much metal being removed from the cylinder walls.
When Chevy did it to get the size down to acceptable Trans-Am requirements, they instead went with a 283 crankshaft into a 327.
Here is what C/D said in a road test of a 1969 Boss 302:
“When you speak of engines in this class of car the Z/28 with its nervous and jerky deportment and ultra quick response in the 12-cylinder, dohc, Italian fashion, is the standard of comparison. The Boss 302 has a temperament completely unlike its competitor It idles smoothly and quietly with almost no mechanical noise and has average response, neither quick nor slow. It could easily find a home in a Falcon and no one would be be the wiser, at least until the Holley’s secondaries snapped open. Ford claims that its new little motor actually makes more power than the Z/28 but, subjectively, the car doesn’t feel quite as fast. Certainly, it doesn’t have the slightly tamed racing car personality which has won the Z/28 throngs of friends. Ford engineers even volunteered that the Boss can be readily launched in second gear and they’re right.”
They also speak of how the Boss 302 doesn’t wind out to high RPM as well as the Z/28, which I would attribute to the milder cam. Other tests I recall have a similar account.
Technically Ford had an engine for that slot up through 1966 – the old FE 352. But it was clearly an unsatisfying solution because it was axed for 1967 with no direct replacement – well the 2bbl regular gas 390 was kind of the replacement.
Imagine one of those old FE 352 big-block truck engines in a Mustang. And the street savvy considered the Mustang 390 an underperformer…
McQueen’s 390 Mustang being able to keep up with the 440 Charger is one of the most amusing movie-magic moments in the old, classic Bullitt chase scene. It’s most noticable in the scene where the cars exit crooked Lombard Street together and then the rear of the Charger can be seen disappearing from view through the Mustang’s windshield like the Mustang was standing still.
The problem with the 352 was that it was physically large and heavy. It wasn’t really a great choice for compact and intermediate cars. Plus, unlike say a Chevy 327, it was hardly a lively engine. While early 352’s were capable of good power, the mid 60’s versions were pretty low performance engines. I equate the 352 to the Chevy 348. It was too big and heavy to be a good engine for smaller platforms.
Yes, Ford pretty much gave up on developing the 352 after the 390 came out in 1961. Which seemed to be Ford’s way, as the Y block got no love after the FE came out (and certainly not after the Windsor), and the FEs were ignored after the 385s were out. Both Chevrolet and Chrysler seemed to get a lot more life out of about every design.
In the what-if department, I sometimes wonder what a 400 tuned to Q-code specs would have performed out of the box. A 400-CJ, if you will.
I agree, a 400 CJ would have been a great engine. Unlike the 351-CJ, if a 400 was built to the same spec, it had enough displacement to have a great low end torque curve. Renowned 351C builder and expert, George Pence, who I have to credit much of his material that made this article possible, has said that he’s built Ford 400s with 4V heads. From what he said, the 400 responds very well to the larger ports.
I think the 351C was the real performance focus, simply because NASCAR was moving towards small displacement engines (366 ci limit without restrictor plates). There was no advantage to investing into a hi-po 400 as it wouldn’t be used for motorsports. Clearly from 1971 forward, Ford had little interest in performance engines, beyond the 351-CJ as even the 385 series became neutered.
FWIW they came very close to releasing a 400-4V in 1977. The magazines
in the fall of ’76 mentioned it, and I even had a pic of an early blank build sheet
from E-Bay that I lost to hard drive crash. It was for a ’77 LTD and the 400-4V was listed as a choice.
More good info Roger. I am not sure if I have discussed that on CC before, but I have accumulated some info on these 400-4V engines. I actually have some pics of the intake they cast for these engines – see below. I suspect with the T-Bird losing the 460 with the smaller ’77 Bird, that maybe the 400-4V was seen as a consolation prize for owners used to big cubes. My guess is that they had difficulty with emissions certification, which is why they abandoned it. In any case, I am sure that a ’77 T-Bird 400-2V would perform pretty darn close to a ’76 T-Bird with a 460.
During this era, Ford seems to of had much better luck with the 2V carbs and emissions. GM, was the opposite, with the Q-Jet which seemed to be easier to burn clean than the ancient Rochester 2-Jet (2G).
“I am sure that a ’77 T-Bird 400-2V would perform pretty darn close to a ’76 T-Bird with a 460.”
Possibly, but my friend across the street had a ’77 Cougar 400, and I flat cleaned his clock with my parents 460-dual exhaust Elite, lol!
Based on past your stories, I think your parents old Elite was a stronger than average, and I am not surprised it smoked that Cougar. FWIW, MT tested a 1976 T-Bird, which weighed over 5000 lbs, and it ran 0-60 in 11 seconds, and the quarter in 17.4 secs. I think a ’77 T-Bird 400 would be pretty close to that.
Ford Guy here got a welcome schooling today, thanks to clear & detailed writing that tied really well into all the illustrations. I’ll humbly admit that I understand all this way better now than I did at the time.
I’ve mentioned that my father was a career guy at Cleveland Engine Plant then Foundry, and I worked some early-1970s summers at the latter, watching block, heads, manifolds and bearing caps being cast for these. Only today did I learn that 302’s front cover was *die* cast, which explains why I never saw any of the tooling.
Nicely done article that will doubtless be “discovered” by non-CC types for a long time to come. I look forward to Part Two!
The “4V” and “2V” thing bothered me as a kid but only because by the time I was becoming automotively aware “V” meant valve to me.
Did someone have a trademark on the word “barrel” as applied to carbs that Ford felt compelled to use “Venturi”?
Well Venturi is the scientific meaning so I’d actually five them credit there, though I’m fairly certain there’s no tiny coiled Cobra acting as a Jet. “Barrel” is about as technical for them as “pack” in six-pack referring to them.
For me it was confusing because my automotive awareness came to fruition when V squarely referred to the number of valves per cylinder or whole engine. As much of an old tech luddite I am now I had to get a deep understanding on how a carburator worked to know what these old Ford air cleaner lids meant with 4V
By the time that Ford was building emissions complaint carbs in the early 80s and calling them “variable venturi” carbs. By then (to my ear) “venturi” sounded positively archaic.
Thank you Vince for this. It’s the most concise story on these engines, which have confused many over the years. Now we have a definitive resource on them. Well done! And I will never disparage a 400 again, despite its 162hp rating. 🙂
Thanks Paul, I much appreciate the feedback! I have been slowly plugging away at this for sometime, so it’s nice to finally get it published. While some versions of the 400 definitely deserve disparaging, it’s Ford and its half-assed engineering/cost cutting (ie the excessive deck clearance problem) that should be disparaged.
Thanks for an informative piece, with excellent research. My grandmother had an early seventies Ford with the 400 CID engine; she was getting on up in years by then and it was the common practice for one of the grandchildren to take her to the store, doctor’s appointments or wherever else she needed to go. Most of us had smallish cars then (I had a VW Rabbit) and it was easier for her to get in and out of the Ford. As I was not married then I was often the chauffeur of choice, which was fine with me. I remember the Ford as having quite a bit of torque but it also had a lot of car to move. The one time I drove the Ford extensively (on leave from the Air Force) I was filling up the gas tank every other day or; as I recall it got around 11 MPG with me at the wheel. We finally convinced my grandmother to stop driving altogether at some point in the mid-eighties and the car was sold. It was pretty rusty by then and it was sold to someone wanting a winter beater.
During this era our family had a 390-2V ‘69 Ltd, a 351C-4V ‘70 Mustang, a 351C-2V ‘73 Cougar and a 400-2V ‘75 Ltd. No surprise that the ‘70 Mach I was by far the fastest of the bunch, with good driveability too. The ‘69 Ltd wasn’t bad for a big car, again with excellent driveability. The ‘73 Cougar XR7, while a beautiful car with a stunning interior, was a total slug. The ‘75 Ltd. was even worse, wheezing along at 10 MPG.
1975 was the first year for catalytic converters in most U.S. cars. I recall one of the big things the manufacturers touted about them was that performance would be greatly improved as engines could again be tuned for performance, as emissions would now be scrubbed in the exhaust, not the engine. Didn’t seem to work out that way. Performance really never improved until fuel injection and advanced computerization took hold ten years later.
No doubt part of the reason that the adoption of catalytic converters didn’t greatly improve performance was because of the Arab Oil Embargo. In the wake of the resulting gas shortages, engines were retuned for better gas mileage, not performance.
Take a look at the exhaust system of a ’75–76 LTD with the 400.
There’s one catalytic converter, in the right leg of the Y pipe…and it’s connected to the right cylinder bank. The left cylinder bank does NOT go through the converter.
Ford’s Better Idea.
1975 was the worst year for the Ford’s 400 power rating, actually for Ford in general. For both Ford and GM, 1975 was generally the lowest hp/ci for most of their engines. While no 400 was a barn stormer, the earliest versions were better. The lack of compression, both static and dynamic, really hurt these engines in real world performance. I know from the road tests I have, the early 400s in full-size Fords were generally faster than the 390s they replaced. In general for most years, the Ford 400-2V performed generally about as well as competitors “350ish” engines with 4bbls, but with the addition of a fatter torque curve.
Thank you for a very interesting article. The pictures and illustrations contributed greatly to my understanding. I haven’t seen anything this informative since “Ate up with Motor”. (Hello Aaron Severinson, wherever you are.)
I miss Aaron Severson too. Wonder what became of his site?
The site is still there. As far as I can tell the last thing posted was from 2018, just over a year ago.
It appears he retired from creating new content. I can relate. 🙂
I’ve been struggling quite a bit lately with whether the site can continue to exist in a regulatory climate that is increasingly hostile toward independent websites of any kind.
It’s interesting how big blocks ranging from 400-455CI are so synonymous with the whole Muscle car era, but the engines that really got the benefits of R&D of the late 60s were smallblocks like the 351C 4V, Boss 302, Chrysler 340 and Chevy’s LT1 350 and Z/28 302
Excellent article!
As a young adult, I briefly owned a ’72 Gran Torino with a 351C 2V, and found the performance very impressive. I’m told the 2V was a better “around town” motor, as the larger 4V ports sapped off the line power.
It also delivered good fuel economy for its displacement, turning high teens on the highway and delivering ~15 MPG in town. These numbers may seem rather average today, but the engine was saddled with a very fat Ford intermediate body, and the driver spurred it quite aggressively at all times.
That’s a terrific point about the 351C-2V being a better daily-driver than the 4V. It reminds me of engine mods that may improve horsepower, but only at the upper end of the rpm band, and it’s at the expense of low-end torque.
That was the situation with the Boss 302. It was fast, but only if you had it wound out all the time, similar to stuff like the Boss 429 and Street Hemi. Any of those detuned-for-the-street race engines were like that.
Thanks Dave. The 1972 iterations of these engines weren’t too bad, as compression hadn’t bottomed out yet (that came in 1973). Ford’s power ratings for 1972 and 1973 were a little wonky, with different rating for different platforms. The engines sometimes seemed to perform better than what the low net rating suggest. Like the 351-2V in your old Torino, it was only rated at 161 hp, but in an old MT road test where a ’72 Torino was compared to a ’72 Chevelle, the Torino performed about the same as a lighter ’72 Chevelle with the 175 hp 350-4bbl.
A good friend of mine had a 72 Mustang Fastback with the 351C-4V and a four speed. That car was fast and could keep up with my modified 302-4V J code in my 68 Cougar. So fast that it took a few extra seconds for that motorcycle cop to catch up with us after our high speed run up Mt. Soledad Rd. to my place in 1975. Clocked 80 mph uphill in a 35 mph zone. We got warnings.
Thank You Vince for the education on all of these engines. Having had the 351W in my ’73 LTD, and all of my friends telling me, “too bad it’s not a Cleveland” at the time makes a lot more sense now. Sounds like I made out ok regarding the better oiling on the Winsdor, as you know how teenagers are wont to drive. ;o)
This also clears up that mystery regarding my friend back in high school with the ’71 LTD and its “400 Cleveland” as he called it. When I commented on that a while back, you replied to correct this a bit, and said that a “deep dive” as some call it around here was coming on all of these engines.
I am much better informed for coming here today, and now know that there is also a familial relation between my first car, and my old ’88 5.0L (ok, 4.9, but well, marketing types!) T-Bird. That 302 “Windsor” was probably the most reliable engine I’ve ever had.
Also, I had no idea that the 351 was actually a 352. Just not an old 352 FE.
So your ’72 Torino? – 400 Cleveland, or what? LOL ;o)
Thanks for the feedback Rick. Not many full-size Fords seemed to end up with 351C engines, and when they did it was always the 351C-2V.
My Torino just has a plain ol’ 400, well actually 408 now. I will have an update at some point on my Torino, and my refreshed 400 engine. Interesting that you call it a 400 Cleveland. A lot of the old articles form they early 70’s call the 400 (incorrectly) the 400 Cleveland.
The 400 is pretty much a direct descendant (or natural progression, if you will) of the 351C; just on a taller block. Ford NEVER used the terms ‘400 Cleveland’ or ‘400M’. But 400 Cleveland is more accurate than 400M; I HATE that term.
Thanks everyone for the feedback and stories. As for the comments on the pictures, I tried to seek out lots of images to compliment the article, and ended up scanning and altering numerous through photoshop.
In 1980, the then-new F series pickups featured the 400 2V as the largest available engine, with the 460 being dropped at the end of 1979. Not that many people were buying big-block light trucks at the time, Dodge had dropped their 400 and 440 at the end of 1978 and GM offered limited numbers of 454’s in 3/4 and 1 ton pickups. Although the 1980 F series was substantially lighter than similar 1979 models, F-250’s and 350’s with the 400 were still quite sluggish, examples I drove seemed to have less power than either the GM 350 or Dodge 360 trucks (both equipped with 4bbl. carburetors). Both the 351M and 400 were dropped from the F series at the end of 1982, replaced by the 351W and reinstated 460. Interesting 1983 was the first year the 351W was offered in the F series, though it had been in the Econoline for some years.
The 1980-82 400-2V was only used in Ford trucks and was the weakest version of all the Ford truck 400s. And don’t get me wrong, I am not trying to say that the 400 in stock form was a powerful engine – most were smog-era specials. The later versions in particular were not great performers. I couldn’t find any road tests from 1980-82 Ford trucks, but I did find numerous late 1970s tests. The Ford 400-2V trucks performed at least as well as the Chevrolet 400-4bbl trucks and both were substantially quicker than the 351/350 powered trucks. Road tests also commented on how both Ford and Chev 400 powered trucks had significantly more torque than the 351/350 counterparts.
I would agree, I was specifically talking about the 1980-82 models. The 1976-79 400’s in trucks seemed to me to be comparable to the truck 390’s.
What a superb effort, Vince, especially as you bother to explain (and put photos) of things I sometimes think I understand, but don’t really.
It must be said that the engine WAS a contender in Australia, as it won the big yearly race at Bathurst (think Indy for Aus, but up and down a scary hill) and various championships in its touring-car career. But then, that’s also because the Fordistes had little choice, as there were strict local content rules for all cars, and the touring cars had to be either available to Mr Public, or close-enough to, meaning that the racers just HAD to make the thing work well. All that said, the teams were plagued by big-end failures all its life, for the reason you mention. Ofcourse, in real-world use, without monster cams and such, they were just considered highly reliable and decently powerful engines.
That Aussie 302W was also a product of local content rules. If Ford had had to import the 302W, it would have meant that its lower-power, lesser-displacement option would have ended up more expensive!
Some meaningless trivia for you, I believe the Aus ’72-’82 335’s aren’t stamped with a “C”, but “GF”, for “Geelong Foundry” (Geelong being the town near Melbourne, Victoria, where they were made). I also believe that all export DeTomaso Panteras made till ’82 had the Oz 351: apparently a local high-end dealer was able to get the cars here cheaper by offsetting the export of the Ford engines somehow.
Thank you Justy. Australia certainly did much more with the 351C than North America. You are correct that the Geelong Foundry castings are marked with the GF, however, many of the earliest engines were imported from the US. Geelong used American cast blocks even after they started local production, that is until Geelong started casting their own blocks. Stay tuned, in part two I get into more of that history.
Canadian/Australian Ford hero Alan Moffat gave his approval in his typically understated style claiming, the “351c could really haul the mail at Bathurst.”
He also praised the cooling system when his big Falcon got a beer carton caught in the grille. While his pit crew were trying to call him in to take it off, Alan just kept on it, later saying the temp. gauge didn’t rise above normal the whole time it was there.
First of all Vince thank you for this incredible write up I love it! You mentioned in part 1 that Chrysler had the poly head engine before Cleveland. Coincidence or more too it ? How similar are both combustion chambers? Do the 385 series 429cj and 429scj and 335 series 351 4v have more in common? Ford base the Cleveland design off of the 385 series or the research they conducted in Indy program early 60’s or did they just copy an old Chrysler
A friend of mine had a ’70 Montego MX with the 351 Cleveland. It had lots of power, but he could still nurse it up close to 20 MPG highway. Another friend had a ’73 Ranchero GT. The de-smogging was not kind, MPG went down the toilet.
Interesting to note that the Aussie 302c is really an offspring of the Cleveland block and not a Windsor with Cleveland heads ala Boss 302. Not really so envious of that now that I know how much heavier it is and the larger (heat inducing) main journals.
Also it was interesting to read from the Ford white paper on how flat the torque curve is of the canted valve Cleveland. The old annual Engine Masters competition that favored a linear power curve saw the 400 SBF with Cleveland (CHI 3v) usually winning. Beating everything including LS based motors. It should be noted that this competition went to hell after they outlawed 4 valve heads when the 5.4 DOHC Fords won big time, but I digress…
I am currently building a 521cid 385 series (385 represents the stroke of the 429), while 335 was the proposed cid of the first Cleveland. Interesting.
Late to the party here:
No one has mentioned that the Boss 302 (1969) preceded the 351C (1970) only because it was a crash program, desperately needed, due to the abject failure of the 1968 302 “Tunnel Port” for Trans Am racing.
The 335 engine development provide an excellent flowing head that was almost a bolt-on. Combining the Cleveland head design with the Tunnel Port block produced a very strong engine with minimal development time required.