We’ve bestowed a lot of love on the slant six hereabouts, especially the legendary Hyper-Pak version. It’s been portrayed as a V8 killer and able to leap tall buildings. But we’ve never had a proper vintage test. Just how fast was it, in stock form, rated at a lofty 196 hp for the 225 cubic inch version? And to top it off, the 225 cubic inch (3.7 L) engine used for this test had the fairly rare aluminum block, making it 50lbs lighter than the smaller iron 170 inch (2.8 L) version.
Did it live up to its much-hyped reputation?
Before we dive in, lets refresh our memory banks about the origins of the Hyper-Pak: In 1960, NASCAR launched a new series for compacts. All three of the Big 3 prepared entrants, but the Plymouth Valiant simply walked away from the Corvair and Falcon, thanks to a special high-output version of its 170 cubic inch slant six, which was inherently more powerful than the rather weak-chested Falcon 144 six and the Corvair’s initial 140 inch flat six.
The modifications for racing were quite extensive, with higher compression, a racing cam, improved valve train, and a really wild ram intake with a Carter AFB four barrel carb. The racing versions also had steel tube headers and of course a large diameter open exhaust. That all explains its ability to turn some 6600 rpm and hit 130 mph.
Since the Hyper-Pak kit was a package of bolt-on parts available over the counter, it did not have the internal changes as the racers did. The cam was not as wild, compression stayed stock, and the exhaust was a split cast iron manifold exiting through a single exhaust with a high flow muffler. It was rated at 148 hp on the 170 engine (101 hp stock) and 196 on the 225 (145 hp stock). That put the 225 squarely in V8 territory, but of course it was lighter, especially so with the optional aluminum block.
Update: there’s some question as to whether that 196 hp rating for the 225 Hyper-Pak applies to the version as used here, which has stock compression. Some sources suggest that it was rated at 196 hp with the high-compression pistons that were originally part of the 1960 170 Hyper-Pak. There’s some pretty good evidence that the 1960 H-P included the pistons, but clearly the 1961 kit didn’t. So it is possible that the 225 H-P as tested here would have had a somewhat lower output.
Among other things, what makes this test interesting and a bit different is that the car, a Lancer station wagon with the optional TF automatic transmission was not changed, only the engine was. This gave a much more direct comparison of the three engines, and was quite unlike any other test I’ve seen like that.
As to the Lancer, it was of course a mildly modified Valiant that arrived in 1961 to give the poor Dodge dealers who had lost the Plymouth franchise the ability to sell a compact. Its styling was toned down some from the Valiant, which was generally seen as a good thing. The Lancer wagon was praised for its good interior room despite its compact external dimension, good handling, a comfortable seating position, and…well not much else was said actually, as the test really focused on the engines and their performance.
Not surprisingly, the 170 cubic inch version was the laggard of the three. Only a year earlier, it had been widely praised for its superior power and acceleration, but once the 225 was made available in 1961, everything is relative. The 170 had to be pushed hard, which drove up fuel consumption. The testers recommended a three-speed manual and a higher numerical 3.55 rear axle if one wanted the 170.
The regular 225 was of course significantly livelier, and yet its fuel consumption was roughly the same as the 170’s. The 50lbs of weight reduction on the front end reduced understeer. It went about its business with less strain, noise and effort. A decidedly better choice.
The Hyper-Pak yielded on average two mpg less, but its performance was “almost as effective as installing a big V-8 under the hood”. Top end speed in the quarter mile was improved by a sold seven mph to 74 mph. the ET in the 1/4 mile dropped from 19.8 to 18.5 seconds. The 0-60 time dropped from 15.9 to 11.8 seconds. All very significant improvements, and the text suggests that the 1/4 mile time might have been bettered some by holding the automatic’s shift points to 6000 rpm.
Here’s all the stats. I was curious as to how the Hyper-Pak stacked up against some other cars of the early ’60s, with hotter sixes or a small V8.
I guess I was expecting a wee bit more from the Hyper-Pak, but it acquits itself quite well against these and others. I was a bit surprised that it wasn’t faster than the ’62 Corvair Spyder, with its much smaller 150 hp engine. Yes, the automatic probably sucked a few of the slant six’ ponies, but then the Torqueflite was generally was considered to not be a handicap, even against 4-speeds. That might have been a bit more the case with the big V8s; I suspect a 4-speed behind the H-P would have done somewhat better.
Of course the H-P slant six still had a significant amount of potential left. M/T had a ’62 Valiant project car a few years back (2016) that was optimized for drag racing and it clicked of mid-14 second ETs.
Related CC reading:
Automotive History: When The New 1960 Compacts Went Racing – The 130 MPH Valiants Cream The Corvairs And Falcons
Curbside Classic: 1961 Dodge Lancer & 1962 Dodge Lancer GT – How Are We Gonna Make You A Little Less Weird?
The Hyperpak “kit” from the dealer did have the internal parts. The kit had high compression pistons, plus a different clutch, along with the parts you mention in the write-up.
PS: back in 1976, my 65 Valiant NHRA stock eliminator car (Z/SA) with a 170 would run mid 16 sec 1/4 mile times
Yes and no. I’ve done a fair bit of looking into this issue and here’s what I’ve come up with. The Hyperpak was of course originally a racing-oriented package for the 170 in 1960. Those engines did have high compression pistons (Jahns, I believe) and some internal valve train parts. To the extent the Hyperpak was sold to the public in 1960 (which was probably very limited) it did presumably come with the HC pistons.
But it apparently changed for 1961, as the Hyperpak became more widely available also for the 225 and more street-friendly. The cam was not as wild, allowing it to be used with the automatic. And no pistons or other internal engine parts were included. That’s not to say that folks couldn’t choose to add them on their own.
It does raise the question of the hp ratings for the 225. I’ve seen that number (196hp) correlated with the HC pistons; others not. It’s possible that the actual number would have been lower with the stock pistons, as in this test. That would help explain why it wasn’t quite as quick as I might have expected.
The reality is that like many things from that long ago, some details are now shrouded in mystery. But it’s pretty clearly established the 1961 Hyperpak package as sold over the counters was all bolt-on and did not include pistons.
I just took my ’62 Valiant wagon on a 250 mile fall drive yesterday into the forests and mountains of PA.
I do not have the hyperpak on it, but it was sure fun.
I always wondered if there is any current history on the Nascar Valiants? I would sure like to find one if it was salvageable and or had any nascar parts left on it.
In your comparison table at the end, I am also a little skeptical of the test results on the Pontiacs. Test vehicles provided by Pontiac in those years were often tuned in mysterious ways by Royal Pontiac before the magazines got them. For example, I wonder about whether the 4 speed alone should have been enough to overcome the Lancer’s 30 horsepower advantage over the 4 cylinder Tempest. The lightest Tempest would also have outweighed the Lancer wagon by no less than 100 pounds.
Facelift-type designs often don’t come off as well as the originals, but I have always liked the looks of the Lancer quite a lot.
Autocar in the UK tested a Valiant 170 in 1960. It had an automatic and a test weight of 3,157 pounds, yet it reached 60 from a rest in 17.7 seconds. I’m not sure that the numbers from this test are good for much more than comparing these three engines to one another.
https://www.flickr.com/photos/triggerscarstuff/12369372393/in/album-72157640642145295
In Argentina this car was called Valiant 2. One of the first Chryslers here.
I wonder how the Hyper-Pak version would have done against Chrysler’s Australian Hemi 6 of 245ci? I think the 265ci version might be the winner.
Outstanding powertrain packaging, and choices. Too bad, about the polarizing styling. Borderline, dumpy. I personally find the styling too gimmicky (and faddish then), to want to own one.
Today when someone says a car is ugly they are mostly just looking at the front. Think current BMW and Lexus These Valiants are ugly front, back and side. Maybe that makes them good like a B-movie, but still.
My aunt bought a Valiant in 1960 and loved it. The car was tight, well-built and for her it had adequate power. As for the aluminum block, as I learned from a service representative when working at Chrysler in the 1970’s, the aluminum block slant sixes were produced to a total of 6000 units. They either failed or soldiered on. No one at Chrysler could figure out why, but the decision was made not to continue production because the company anticipated many problems due to this mystery. I have driven several slant sixes including a 1978 “Super Six.” Let’s not get excited about performance of these power plants but when it comes to reliability, they are wonderful. Since I was not going to fuss about drag-racing with every car at every red light, the Slant Six was fine for me. Remember: place car into gear (automatic transmission) and then wait for the engine to react. Do not yawn during this interval because Slant Sixes are easily insulted.
Before the Viper helped wake up Chrysler’s generally staid ’80’s reputation of K-Cars and minivans, bringing back the ‘Hyper-pak’ brand in some marketing capacity, would have been interesting. It’s a great catchy term, that aged well. ‘Hyper’ as a catch phrase, being big then. Would have went over well, in the right application during the ’80s, and Direct Connection era.
This would have been a great cult tune, to use in accompanying commercials.