The decision to essentially merge GMC and Chevrolet trucks in 1968 had several repercussions. Chevrolet would have access to GMC’s HD truck line (and engines), rebadged as Chevys. And reciprocally, GMC would start selling light and medium duty Chevys as GMCs. This was the beginning of the end of what had been two truck makers that mostly had shared some cabs, as well as pickups and light vans, but with mostly unique engines.
This GMC ME-6500, technically a medium-duty truck, is hauling a good sized load and is all-Chevy, except for the badges. And the badges on its sides proclaim that it’s got a Chevy 427 V8 instead of one of GMC’s big V6s.
As a frame of reference, GMC’s “own” conventional medium and HD had this cab, which shared nothing with the Chevy.
It came in short nose and long nose versions. We’ll do a more detailed post on them one of these days.
Back to the Chevy- GMC: I should point out the 366 and 427 Chevy Mark IV truck V8 engines were not exactly the same as those used in Chevy cars and light trucks. The biggest difference was that these were tall deck engines, meaning the block deck height (top of block) was higher, so that longer pistons with four piston rings could be used. That improved durability at the constant high loads these engines were subjected to.
These are referred to as “tall deck” 366s/427s. And there’s other differences of course too, from sodium filled exhaust valves to heavy duty components all-round, and of course the accessory drives are set up for truck use, for air compressor and such. The Holley four barrel has a governor, which works off the mechanical advance distributor, limiting max. revs to 4000. These were of course tuned for maximum torque and continuous power output, and at full chat, exhaling through two big short pipes, they were somewhat famous for their vocalization. And their prodigious thirst. The 427 was rated at 260 gross/ 230 net hp.
I have this miniature 6-71
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Over all the merger was a pretty good deal for GMC. GMC’s V6’s IMO were not in the same league as the Chevy engines. The GMC’s were tough but they had there issues and required more maintenance. The worst of it is this all unraveled as GM bumbled along. 1980, GM drops Chevy Titan, Bruin and Bison trucks.
GM still doggedly clinging to the 2 stroke diesel engines but the emissions hand writing is on the wall, Thanks John Rock.
1986 GM sells HD truck line to Volvo, IIRC GMC had about 17% market share at the time.
John Rock moves on to Oldsmobile.
1987 Bus division is sold off.
1992 New Chevy and GMC medium duty trucks, vast improvements over previous model.
2009 GM throws in the towel and exits the medium duty market.
GMC trends more towards the “Luxury” end of the market, what a reversal! I can’t tell you prior to this shift that I had heard people that they bought a GMC because they wanted something a little more “heavy duty” than a Chevy.
2018 Chevy reappears in the medium duty market with a Navistar joint venture truck. Note – no GMC version of these trucks.
That’s just about exactly how I remember it! I thought it was very interesting the heavy truck sales brochures in 1986 and 1987 started to picture Astro 95’s and the like with Cummins engines in them. Still, with the excellent Detroit 60 on the way is funny they sold out to Volvo when they did. I saw a few very late Generals and Brigadiers with 60’s in them
Only saw one General with a 60 Series in it.
I remember one on the GMC bigshots lecturing us back around 1981. GMC wasn’t going anywhere. GMC could supply every truck a company needed from linehaul to the parts runners pickup. GMC had their own engine and their own transmission. GMC was able to leverage engineering used across multiple platforms to keep costs down, etc., etc.
The trouble with line of thinking was the bigshots were out of touch with the market.
A lot of customers were done with Detroit Diesel 2 strokes and the 60 Series was years away. The 60 Series was a hit, when I visited the engine plant around 2005-07 the person giving us the tour showed us the warehouse area stacked full of bare blocks waiting to be machined, every casting in the room was sold, no engines being built for “stock”. There was a handful of 8V-92’s still being manufactured and once the back orders reached a certain level a run of 6V-92’s would be built. The 60 Series was a great engine but a little massive, heavy and sort of a dead end. The DD Series that followed the 60 Series went back to the gear train at the rear of the engine and has been a successful engine line.
The Allison transmission was expensive to buy, repair and they could be trouble some. The World transmission would not arrive until 1991. The World transmission was a home run, still expensive but with 6 speeds and developing a good reputation sales were good. I remember in the late 90’s that a truck order with an Allison might have had close to a year waiting list.
There was also the production constraints at the GM heavy truck plant. When the market was hot the plant ran at full capacity but it wasn’t enough and the order bank kept backing up and deliveries got longer and longer.
So GM finally has a world class engine in the 60 Series and hands down the best automatic transmission on the market and no HD trucks to put them in.
Have you ever operated a 60 series? I have and they suck! Slow off the line slowest I’ve ever experienced to get up to speed and lose revs to fast in between gears. I’d much rather have a hummin’ Cummings. Although I must say that the Mercedes engine that sits in the Mack I currently operate is a strong runner.
Your funny, over 1.2 million sold and the value if 12 and 14 litre 60 non egr engnes in clean chassis pre 2000 trucks have gone through the roof like 6NZ Cats and you don’t hear of anyone screaming for N14 or Bigcam Cummins (although redtops good engines) in the current market. Glider builders do Cats ànd Sixties. Its well established its legacy along with being the WORLDS FIRST ELECTRONIC four stroke diesel engine that lit a fire under every other hd engine builder in the world. –Dieseldog!
I think your dates or memories are off; Astro (and other GMC HD) brochures showed Cummins engines back in the 70s…
“Over all the merger was a pretty good deal for GMC. GMC’s V6’s IMO were not in the same league as the Chevy engines.”
The engine families never directly merged. The Chevy V8s were used for Chevy/GMC’s medium duty 50, 60 and 70 series. The GMC V6 family were used for Chevy/GMC’s heavy duty 80 and 90 series at the same time (later called 7500 and 9500 series and Bruin/Brigadier).
The GMC V6s were heavier engines meant for heavier loads.
SemiOT: the latest Collectible Auto mag shows a rebadge I hadn’t heard of before. Through the ’40s, GMC sold Maple Leaf trucks in Canada. Appears to be the same as the GMC, except that the long badge on the side of the hood says MAPLE {} LEAF with a leaf between the words, instead of GENERAL MOTORS TRUCK.
This isn’t nearly as well known as Fargo or Mercury.
Maple leaf trucks came to NZ they were claimed as better than Chevrolets and like Bedfords ran a full pressure crankshaft, Ive seen a couple in collections they aged out of commercial or farm use long ago.
Chevy did have a version of that GMC medium/heavy duty cab, only with single 7″ headlights and a “Chevrolet” inbetween. Extremely rare.
I think a good bit of politics remains between GM and the dealers, and is probably reason #1 why GMC even exists today. Arguably it’s hurt Chevy when you consider the brand perception comparison with Ford. GMC, as a division, is a moneymaker and it gives Buick dealers a truck to sell.
My contention is that neither Buick nor GMC needs to exist, and the sooner GM pares down to Chevy and Cadillac covering the range that all four brands currently cover, the better. Best way to accomplish that is to continue offering more premium Chevies, as Ford did for decades until Mercury was no longer relevant.
Agreed – Buick and GMC are legacy brands that exist only because it’s easier to keep them around than to kill them off. I can’t imagine GM would create an intermediate brand (or two) now if they didn’t already exist – Toyota, which sold more cars than GM last year, is likely not thinking they could do even better if they had something to fill the gap between Toyota and Lexus. Also, Buick now has a SUV-only lineup that doesn’t contrast much with the GMCs in the same showroom. On the other hand, it should be noted that Chevrolet and GMC full-size pickup trucks combined have sold better in recent years than the Ford F-series, so it could be argued that GM’s two-brand strategy is working.
(note: I’m talking about North America here; Buick in China in a whole ‘nother story and obviously worth keeping, and its success there is probably part of the reason it still exists elsewhere).
Toyota had more chips, make no mistake. GM or Ford would have outsold Toyota had they been able to meet demand. Ford, for example, outsold Toyota in Q4.
Toyota did add another division, Scion, and if it made the kind of money GMC does for GM, they wouldn’t have killed it.
Hmmm. So killing off Pontiac and Oldsmobile was easy… and somehow killing off Buick would not be?
I’ve always wanted one of those big GMC or Chevy grills to hang on my garage wall. Or like the one below.
I have never been a truck driver and I’m not sure of model year of the attached GMC rig in this picture , guessing late 70s but if GMC ever decided to use a GMC rig for a promotional ad this would be top pick I’m sure , I have always liked the older rigs especially the earlier machines , In my opinion they present a more classier touch of originality
that is a beautiful picture nice flash from the past.
GMC division came up with a new medium duty conventional in 1966 known as the ‘E’ series. These trucks used the same cab as the heavy duty trucks pictured, but on a lighter frame with smaller hood and front fenders. The E series trucks featured GMC V-6, Chevy straight 6, and Toroflow diesels. The E series was replaced in 1970 with these rebadged Chevy designed C and M models. At the same time, some of the smaller GMC V-6’s were offered optionally in both Chevy and GMC versions along with the Toroflows.
We had a couple C65’s with 366 engines on the farm. Good trucks back in the day. 3 actually. A 1975, 1976 and a 1977. They were good sugar beet haulers. I will say they each ran a little differently from the other as far as power under load went. But good trucks all the same though cabs were drafty with heaters in name only. Good memories.
Brian…good on you for remembering the 366s and 427s from their beet hauling days! What I wouldn’t give to hear one of them pulling up to the piler at full bark during harvest. I’ve driven beet truck in northeastern North Dakota for American Crystal growers, and my Dad spent 38+ years in the sugarbeet industry (with American Crystal.
In the late 60s I knew of someone with a straight dump truck Chevy like this with a 427. He said he could haul 1 extra load a day because he could accelerate better around town. Only question would be the total life cycle costs with rebuilds diesel vs. gas.
I have a couple GMC trucks on the Farm with the 427 engine a 1975 tandem axle with 5+4 transmission and a 1980 single axle with 5 speed and 2 speed axle. The single axle was a 366 originally. It was upgraded because when my cousin owned it he couldn’t keep up with a Ford Louisville with a 391.
At my second job, I worked for a feed store (Purina Chows)
The owner was not a car or truck guy bought a 1974 GMC 7000 with a 24’ box from an express cargo company. It needed an engine so they replaced the 366 with another. It caught fire, but the truck was still good, so he has his mechanic put in yet another engine. This time the shop found him a 454-4 with dual exhaust from a junk yard!! They suggested he upgrade the four speed ( a three speed with an extra low first) to either a five speed or a two speed rear axle.
He wanted nothing to do with that!!
I remember using that to pick up feed some 50 miles each way. One time they loaded me with what I’m estimating would be close to 15000 lbs (pallets of ten-50lb bags, two rows, nose to tail). That old 454 didn’t even feel like the weight was back there! I started up an on ramp, ran through all the gears wide open and was doing 62 by the end of the ramp! I was so impressed with a truck that had been run so hard yet never failed that I’ve owned several light duty GM throughout life.
Well, I used to own THE V8, the 637. So de-rated it made me cry. Nothing to compare, except maybe a Hall-Scott (never drove one). The V8, end of story.