People talk about how "under powered" the GMC V6, Twin 6 and 637ci V8 engines were, not realizing that the engines absolutely can make WAY more power than they released with, but that would shorten the life of the engines and increase maintenance costs. These engines were GIANT, over engineered to be simple, reliable and made to last. By tuning them to turn slow and make a ton of low end torque, the engines can get big loads moving more easily and not be stressed to the max when the engine is being run hard. These were never meant to be performance engines, they were meant to do work. And that is something lost on a lot of folks today that are used to big rig torque and power in their 3500 series pickup.
Good post. A lot of car people seem to get confused over the distinction between a high performance and high torque engine. They're not the same and the 'high performance' engine isn't necessarily the better option in many applications.
With the gearing that they mated them to they’d pull the Empire State Building from NYC to Miami. I’ve watch vintageiron do a full rebuild on a 305 6cyl and they were so overbuilt for the work that they were intended to do. They also had technology such as a waterless intake manifold and cathedral ports decades before the LS platform ever existed. I’d love to have one of them to restore.
I read years ago, maybe below a write-up on curbsideclassic, a guy wrote about having just the 305 V6 in a half, 3/4, or 1 ton truck. Think he was on a logging road working for a logging company back in the '60s, can't remember what he said he was pulling with that truck. He wrote, you could let the clutch out, and it wouldn't die, and it would pull that load at idle. Maybe same guy I read years ago, someone put it best...."lugged most like a diesel of any gas engine I ever drove."
@@masjuggalo That was a very rugged V12. With the heads removed, look at the cylinder wall thickness. Paragon Oil (Gulf oil distributor) on Long Island, in the mid- late 1960's had some GMC 9500 series short nosed conventionals, tandem axle tractors, ran these V12's, and I saw and heard them, remarkable and impressive. In 1966 I was 13 years old and recall them very well. Those I saw hauled 9200 gallons of no. 2 diesel fuel.
I had come across one in a 1965 gmc truck in a junk yard back in the late 90's. I had no idea what kind of engine it was but I remember the spark plugs being on top instead of by the exhaust. Had I known what it was I probably would have bought it just to have.
For those that haven’t seen the V6 version in person, the engine shown at 3:00 is the size of a big block chevy and heavier. Heck the water pump on my 305 looks like it weighs 50# by itself. Cool old engines. Thanks Adam. 👍
@@emilyadams3228 uncle had one in his 67 GMC truck idk which variant but probably one of the way bigger bois considering he pulled a damn semi out of a ditch with it LOL
Trying to overhaul one be a nightmare. Hand fitted, Bearing and pistons often half of a thousandths bigger or smaller than spec. And still there was persistent bearing crank, and head gasket failures. Newest Gen seems to have fixed a lot of those early problems.
Back in the 80s a buddys dad had a small excavation company,had a GMC with the 305 v6. Us kids kinda chuckled ,didnt look like no chevy 305 but looked more like a rat motor😂 A v6 with v8 sized valve covers
I worked at a GMC dealer,77-82.Did two long block changes on the 637.The dealer got two new factory long blocks from GMC.They were in the J model tractors with Fuller RT613 trans.Heavy piece of iron.Sure ran smooth.On the two barrel carb it would pour the gas into the engine.
The Turo Flo injectors were located were the spark plugs where in the gas versions,and the V-6 Turo Flos,also incorporated or utilized a balanced shaft .I think the V-12.was discontinued in 65. When I worked at an International truck dealership in 74-77 the serviced a fleet of cabovers that had the GMC V-8,I remember driving those trucks,you could roll the clutch of idle with out a bit of protest,those engines had amazing torque.If you ever drove those GMC medium or heavy duty trucks,you never really ran high RPM,they were ment to be ran at low engine speed,a great family of gas engines in my eyes.
@@samholdsworth420 There is a RU-vid video of a C-10 pickup with a 472 V6. UNfortunately The guy doesn't use the wonderful 750 rpm torque. Instead he tries to wind it out in each gear and it's not impressive (any big block Chev V8 would run away and hide from it.)
@@patrickshaw8595 I saw that video. Yes I agree, short shifting it would make the truck accelerate faster. Not many combinations can lay claim to that. A truck should pull the hardest at its shift recovery rpm, not after being wound out. Torque rules. ---Doozer
@@kooldoozer International gas engines and I am referring to the 266,304,345,and the 392, were the only other truly designed over built truck engine that was available in light duty pickups, Travel alls and Scouts,besides the GMC V-6 truck engine family.
I worked with the Medium Duty team at the GM Truck Group in Pontiac 25 years ago. Back then, the gasoline powered medium duties were important to customers who operated in areas where diesel fuel was not as readily available. GM offered the CAT diesels back then, but the 454 gasoline engines were popular in medium duty. GM had many customers who preferred the gasoline engine for their application.
We've got the Isuzu/GM cab overs at work, both gas and diesel. Overall, the gassers tend to have lower repair costs and I'm able to get parts generally faster than the diesel version. Gas is preferred in residential areas and local city work, while we use the diesels for long highway runs and heavier loads. They might be slow and ugly but they're damn sturdy
@@MrChevelle83They were available in 1979 and 1980. They were tall deck blocks on top of that. Lost a bet on it. Saw the truck and the option sheet in the glove box. The intake had 2 thermostats, denoting a tall deck. Governed Holley as well.
@@thegreenerthemeaner thanks for the info, several years ago i bought a 366 due to being told it was a 454, I scrapped the engine and wished ida got the crank shaft out of it for a 396 block I had at the time. I didnt have access to casting numbers then like we do now.
Had a 534 ford to pump irrigation water and it was a lemon apparently. It was sized right according to hp required but just couldn’t do the job without constantly breaking down and laboring like it was going to blow up any second. Well, it soon did blow up. We replaced it with a Ford 460 turbo charged and that thing ran like a champ for over 25 years. Only needed valves replaced as it was run on natural gas.
I have never heard a good thing about those Ford Super Duty engines. Another thing about them was they had a cylinder head/block configuration like the Chevy W-motors.
I seem to recall I rode to grade school in a Gillig pusher type school bus with a Ford 534 mounted in the rear. It climbed up a lot of hills were I lived in on the San Francisco Peninsula.
There is a boat engine that put twin turbos on the 534 & still used draw through carbs. Apparently they absolutely DRANK gas but had decent power for the time. Seamaster i think it was called.
We had a 534 in an 10 wheeler grain truck on the farm abused it many a year don't recall many problems with it other than a few carb rebuilds tune ups but that noisy Carter electric fuel pump away gave us hell lol
Not sure, but I believe the superduty series was kind of a gift from Cummins, they attempted developing a diesel v8 with it, but really never got far enough out of R&D to continue. The heads had one big intake hole near the center that never flowed well, it had several thermostats to create different temperatures in different areas of the block and heads and intake manifold, .. nightmares!
I had a 305 and a 478 v6. They made Toro Flo diesel out of these. GMC also made a huge straight 6 truck motor. IHC made huge gas V8 and 6 in trucks also .
100%. This is when the internet is such a blessing. About 10 years ago I finally started looking at the GMC book I had for a while. Eventually, I started looking up everything online I could find about the Ford 534, IH 549 etc. But this "family" something on it's own. 305, 351, 401, 478, the 702 V12, and the ToroFlow diesels. In the early '70s they put the longer stroke crank into the 351 to enlarge it to 379. And a 432 doing the same, 401 with the 478 crank. Eventually when a guy finds articles & discussions about the 702 V12, someone always brings up, too bad they didn't double the 478 instead of the 351. The diesel 637, 478, for a few years they made a 351 of the diesel, saw a pic years ago, GMC had put a few in 3/4 ton pickup trucks, and supposedly was toying with idea of offering that to the public.
Those big GM V8 engines from late 60's thru the early 70'swere really something. You'll never see them again. My father bought a used 1969 Oldsmobile 98 Luxury Sedan that was in like new condition from a gas station owner he was friends with. It had a big GM V8 with over 400 cubic inches. When we would take a trip to Michigan from Milwaukee, to use a trailer on a lake my aunt let us use, the car was fully loaded with 6 kids, 2 adults and a huge trunk full with luggage. Even with all that, that big V8 had so much power it was just loafing along on the freeway.
The 702 twin-six was not coupled together. It had one casting of the block, it had one forged crankshaft, 4 separate heads, 4 separate exhaust manifolds, 2 carburetors and 2 distributors
I fixed up a 64 GMC and resealed the engine. No need to rebuild as these were 2X overbuilt as compared to a Chevrolet engine of the same time period. I added Holley Sniper to the 305 and you could lug it to 600rpm without protest. Super cool engine. Also GMC rated the engine as Net power not gross power which was common practice so they made more power than what they were given credit for. Special grey cast iron, hardened valve seats with rotators, and I believe 3 compression rings and one oil control ring. High flow oil pump and coolant pump. That 305 I believe took over 9 gallons of coolant to fill.
There was a contractor that I worked for that had all GMC trucks. A few of the dump trucks had them big V6 engines even huffing oil all over they still made monster power. He had 3 utility bodies one was 66 that had I think the 305 motor. What I do remember most is them giant oil bath air cleaners & replacing radiators and or running em to Circle S auto parts to have em gone over and soldered up. Yes they took monster amounts of anti freeze. Usually in April he would send one of us to that auto parts store to buy like 10 cases of anti freeze as well them smaller barrels of oil usually Penzoil or Quaker State . Back then a case of antifreeze had 8 gallons in the case. When he sent me I had a crazy list of all kinds of filters in my pocket. The other fond memory is how them utility body trucks rode like an amusement park ride especially loaded with tools.
The small block Chevy 305 engine made its debut in 1976, designed by General Motors as a small V-8 that would provide improved fuel economy, while also sharing design and components common to the popular 350 engine to help reduce production costs, so no way this was the original engine, maybe a 283?
@@charlesnorris2993 More like the 263 maybe 265 I believe??? It was an odd ball small block V8 in that one utility body truck. The shape of the weird valve covers always fascinated me. It was not the 283 that was mostly in cars until the late 60's when GM started putting em in light trucks... I'm just too busy right now to look it up. The engine had a really weird top end on it & only a small scrawny 1bbl carb for a damn V8 engine. Most of the 6cyl on the utility trucks had 1bbl carbs too. Some of the dump trucks with the 6cyl had a massive looking carb on em and really giant oil bath air cleaners. All of this trucks were GMC nothing else. His name was Howard Bailer. Allentown Pa.
Large dump truck a local farmer had featured one of these, did tune up on it and was amazed at how smooth ebgine ran, was only one Ive ever seen. Big motor!
When I was a kid I remember my Grandpa talking about swapping truck motors into cars and I'm pretty sure these are the kind of truck motors he was talking about.
I'm not saying you are wrong. These engines are extremely heavy, you can look it up. Just a guess here, I've read quite a bit over the years, from what I've learned, the GMC inline 6 truck engine was a popular swap that guys did after WW2 in the late '40s and the 1950s. Not to be confused with the Chevy stovebolt 6 etc. These were heavy duty, quality, more hp, torque, the 270s were in a lot of military vehicles in WW2, I think a lot of young guys found out, that's one hell of a quality, well designed, well built engine, and makes a lot of power. Now I'm not sure how popular the 248 GMC was, or if some guys just settled for it, but the 270, it's my understanding, that a lot of guys in that era used in dirt track race cars etc Whether they got them from a multitude of applications (?) commercial-type trucks, bur I'm pretty sure a lot of 270 GMCs were in "deuce and a halfs" as they called them 2.5 ton trucks used in the war, among other military vehicles. Less common, but more desirable was the bigger 302 GMC, 😁 (4.00 X 4.00) , also a truck engine. There was a time those engines were dominating certain types of racing, like dirt track. I'm 49, not 89, I only know what I've read, eventually, signs were put up at many race tracks banning "truck engines" , and old timers who were around at the time claim this rule was targeting the GMC 302 specifically. There are videos of guys with those old "hot rodding" type cars (I think of '30s Fords & Chevys), with 270s & 302s, so apparently it really was "a thing" quote unquote
@@Sheisthedevilyouknowwho-ft9weI've read about guys putting GMC bus engine blowers on the sixes for racing. How they did it, I don't know. I've never seen a picture of that.
@@Sheisthedevilyouknowwho-ft9weI know of an old timer up in alaska that has a deuce and a half engine in a 60's truck. it's pretty neat. unique sound. he told me in the older times when he raced, that he would use a pontiac two barrel on a tri power intake to get more cfm on the inner carb and let the outer carbs be.
I got a chance to work on one of these back in the eighties. Took the heads off ground the valves and seats. I remember thinking how big that hole was when a 6" extension fell down into the cylinder😮
I've only seen 2 of the 637 V8's in GMC dump trucks in my 67 years!😄As for big V8's, Ford also had a monster 'Super-duty' series for medium to heavy duty trucks (and marine use) from 1958, all the way till 1981. There were 4 different versions. A 401, 477, 534, and a twin-turbo 534 developed for Seamaster Marine, called the 'Super Seamaster 534-TI-B' that made 400 hp. and 657 ft. lb. of torque! They were big, slow turning V8's that maxed out around 3400 rpm, but made gobs of torque in the low-rpm ranges where it was most needed for heavy loads.😉
@@whathappensinmaine5463 🤣👍 I hear ya.. 331, 361, and 391's were all industrial/truck engines that seemed like gutless wonders until you started loading them down. They used a bunch of them in the F500 - F700 trucks back in the 1970's.
@@danw1955 yep, i did find out if you just dump the clutch in 2nd it will spin tires tho. Did it coming off a stop light on a hill and it just lit the right rear up🤣
I used to own a 1964 GMC Suburban 4x4 with the 305 V6 a granny 4 speed and 2 speed transfer case. That thing could pull absolutely anything I ever stuck behind it . I once pulled a big ole Chevy 2 ton flatbed loaded with firewood about 15 miles through the Sierra Nevada Mountains back to civilization. Up steep hills and through a 2 ft deep creek etc. It had broken down on the guys cutting up firewood and I had just happened by them. That old GMC and that 305 V6 wasn't going to win any races but it never broke a sweat pulling that big old Chevy truck full of firewood. She sure was Thirsty as far as fuel was concerned though.
At the 5:00 mark you said exactly what I was thinking when I read the title: Buick and Ford cut cylinders off to make a V6 or a V8 with the wrong angle, and here GMC added cylinders to the wrong bank angle (though it's weird, the pictures of the actual V6's look like 90° spreads to me.) It's also odd that they went over-square, when one would think that would make it less of a torque motor. Finally, of course, the bitter irony that they knew how to make a balance shaft to fix the angle problem, but it took Buick two decades to adopt it...
Yeah, it’s amazing that all big inline-4’s of the 20th century didn’t employ balance shafts. Many of those things were ferocious shakers. And yes, that Buick V6 was horrible until they went to even-fire (offset crank pins). Anyhow, balance shafts were patented in 1907 by some guy named Lancaster, so it’s surprising they weren’t widely used until the mid-70’s …
@@Clyde-2055 You know it's funny, I don't remember the 2000 & 2300 Pinto engines being rough, and they had very slick 4-speed transmissions. I started speed shifting without even thinking about it.
@@marko7843 - “An inline-four engine has a vertical vibration (at twice the engine speed). These imbalances are inherent in the design and unable to be avoided, therefore the resulting vibration needs to be managed using balance shafts or other NVH-reduction techniques to minimise the vibration that enters the cabin.” Before balance shafts were widely used on these engines, manufacturers isolated the engine and transmission on soft mounts to minimize vibration transfer to the body. If you’d ever had an engine or transmission mount collapse such that the engine rests against the frame/body, it would rattle your teeth. The larger the engine, the more pronounce was the vibration. The threshold seemed to be 2.5L (150 cid), above which the roughness was difficult to quell. The worst I remember were those large GM and IH “half-engines”, the GM being 194.5 cu.in. (half a 389) and IH being 196 cu.in. (half a 392) - those things would out-shake hell ! Aside from being an annoyance, these vibrations would also shake engine parts to pieces, especially accessory brackets and mountings.
2 barrel carbs were good for quick acceleration at slow speeds, say you only really needed to get up to 30 mph. Say in a taxicab. The GMC V6 was used a lot in school buses and garbage trucks.
Hello frien, I'm an old retired mechanic. In the early 60s, Ford offered a 534 V8. I believe it was 534. I worked for a construction company, We had 2 Ford F550 single axle tractors with 534s. The intake was massive. I live in Florida. The used these same engines in orange groves. Back in the 50s & 60s farmers combated the cold by using short towers with a propeller on it to push the cold out of the orange groves. You still occasionally still see these towers, now a relic. They were powered by 534s. It may have been classed industrial, but they were in trucks. Note, the 550s that had these had a bubble top. The roof was higher than conventional. They were referred to as high hats.
Our first C-Cab chassis American LaFrance pumper in 1965 was a 534. Had until May 92. Second ALF With a C-Cab was a 3208 and our first Auto in 1980. Ran until 2006. They always said the 65 with 534 was no slouch at all. Just hungry lol. Neighbor dept was mostly GM plant guys, they had a GMC COE under an old FMC body. The big V6. No Guts lol.
As a marine mechinic I say nah. Diesels are better suited for boats in almost every way except perhaps speed. I hate working on them. Nothing like being a in a bilge full of highly explosive gasoline vapors and hard to avoid if you're doing anything with the fuel system or just basic maintenance and troubleshooting.
I don't think the balance shaft had anything to do with refinement. Probabaly had much more to do with the engine not beating itself to death. I have been wrong before though.
The GMC 702 V-12 was NOT a twin 6. It had a specific single casting 12 cylinder block. It did use 4-3cylinder heads. But it was definitely a singular made V-12
Yup, I was going to comment the same thing. Single piece crankshaft too. Two v6 intake manifolds. What I liked was the unusual distributor they came up with to drive the 12 sparkplugs.
I remember working on these engine in Coca Cola delivery trucks with my pops. Had to run over head adjustments every 15 to 20 k miles because some had solid lift cams and lifters and that was done with engine running, valve cover off (of course),, bit of an oily mess. They would tac out so fast cause of the stroke in these old boat anchors. Brings back memories.
if you think that's cool you should check out Pontiac's OHC straight six from the 1960's or Buick's all aluminum 215 CI V8 or Jeep's F-head or Ford's 427 hemi-head or or or
I had a 62 GMC with the 305 V6. Did a full rebuild on it, I think 40 over pistons, cam reground to a modern profile, ported the manifold and put on a Holly 500cfm carb, electric ignition and shaved the heads to bring the compression from something like 7.5 to 8.0. It really moved and felt like a totally different motor. Yes I could have just stuck in a 350 like everyone else but this was more interesting. Except for the parts stores that always said..no sir the 305 is a V8 it's not a 6 cylinder.
I had a counter person at a GMC dealer ship,that when I was searching for a pair of PCV valves for a 305E and was told "Hold on partner, they didn't build a 305 till 76,and make sure I know what kind of engine I am working with before I came back. I replied thanks,I will do that.
You forgot to mention the Ford Super Duty truck engines of the era: 477 and 534 cubic inches. The V12 was not two V6's coupled together. It had a one-piece block casting and a one-piece crankshaft forging.
We had Jeeps with the 401 in them and they would power them just about anywhere and was super reliable as long as they are not over revved and beat to death constantly.
The 637 was a "Boat Anchor". I put an Olds 455 in my truck - it had much more power and way better fuel economy(4 barrel Quadrajet) It was under square at 4.125 bore and 4.25 stoke and a torque monster. This is a very smooth and quiet V-8!
America has Fallen so Far. Its sad. You couldn't give me a new 2024 vehicle made by parts from 10 countries. I never thought in my 62 yrs America could fall so Bad. I miss the 60's- early 90's..Great Video. Thanks for the Memories
I've got a great book about GMC (the whole history of it),from around 2002(?). It covers this family of engines, too. I recommend it if youre interested in old GMCs at all. Thanks for making this video Adam, and get the knowledge out to more people 👍
When my metalhead biker pal saw my 65 GMC for the first time, in 1989, he said "That was when a truck was for a working man." She had an all-steel, grey-painted interior, with a black rubber mat that covered the whole floor. The seat was the only soft part.
Great video. Thanks for posting. Back in the early 70s a fellow put a 427 out of a gravel truck into his 66 or 67 Impala. Monster torque. He'd put the front wheels against the concrete parking blocks and sit there spinning the the tires barely over idle. 😊
Two yachts we serviced ran the Turo Flo's diesels. One had a massive Switzer turbo and the other two RaJay intercooled, both were twin screw. One always limped in with a blown head gasket(The "Mucho Gusto"). We told the owner to shave an inch off the wheels until it stopped but he said he didn't want a slow yacht. Seemed like 3/8ths inch between the bores made for a small engine package. A PITA to work on in a yacht environment.
Awesome material, again... You mentioned many stuff that i'd really like to see in future videos: the GMC V12 twin six, the toroflows diesels (especially the twin supercharged), the whole range of GMC' V6s, and the AMC 401 c.i. Ford and Dodge V6s of the era would be very interesting subjects too. Addictive channel.
When I went to technical school to be a mechanic the only time my life I've seen a Cadillac 500 was in that school. I was amazed at how slow it was. This was in 1989
It is absolutely worth noting that the 2022 COPO Camaro came with a 10.4L V8, 632 Cubic Inches, making 1004hp. It’s weird that people have become trained to jump straight to the Cadillac 500 or Viper 8.3L when the COPO Camaro beats them in displacement by a Civic engine. Sure this is 5 cubic inches larger, but even with mods 400hp is basically out of the question with these engines because they won’t spin the RPMs to make horsepower with all that torque. The COPO 10.4L is basically just a 4-bolt main tall deck Gen VII Chevy Big Block. US based drag racing engine builders have been building something similar for years: it’s a tall deck, big heads, a fat cam, forged internals, high compression, and all the displacement that will fit in the package. Chevy has offered a 572 crate engine for decades, and this is basically just a stroked version of that (maybe pistons are 0.5mm larger), but it’s actually in a production CAR. Meanwhile the 60 degree V8 weighs 1300lbs. The twin six is closer to 1500lbs. The COPO engine is winning by a small block (550lbs) in weight, at 700lbs.
There used to be GMC chassis based school buses,I understand had 351 or 390 cubic inch V6, 1950 to mid 1950's ? had a loud exhaust resonance at certain speeds under load,sounded "poppity" like exhausting through a trumpet.
There existed much larger engines in road going vehicles around this time period. One of my buses originally had a 779 ci Hall-Scott gasoline engine, and the 1091 ci version was used in fire apparatus as well I'd imagine both of them were used in heavy trucks of the day.
Work on a farm many years ago. They had the GMC coe trucks with the 401 V6. Super reliable and durable. Both were governed to 3700 rpm. Other than cleaning the points and changing the oil and plugs, they just kept running.
I think some people watching this may be wondering why such a large displacement engine puts out so little power. This engine could easily have produced double the power if it were built to handle higher revs, but it was limited to 2,800 RPM which is well below the power band for a gasoline engine. Gas engines generally start making power above 5,500 RPM and the peak depends on how well they flow, and other factors. I guess truck transmissions of that era were designed to work with typical diesel power bands that would normally peak below 3000, though if the engine was built to produce 600-700 HP it could have expanded its potential applications beyond just trucks.
Ford made a 1100ci all aluminum DOHC 32V 60° V8 in the early 40s. It was originally a V12 intended for aircraft use but other manufacturers beat Ford in bidding wars so they took 4 cylinders off of the casting and used them in Sherman tanks.
that type of engines are excellent candidates for marine conversions to use on medium sized pleasure boats however, I never saw such a conversion. much better than car big blocks for that application.
Very similar in use to fhe 366 GM truck engines. They don't rev, heads don't flow, but they made torque EVERYWHERE and if left stock, literally would never die.
Forgot to mention that lots of drivers complained about the exhaust note on the 478 V6. Some couldn't stand it as it would make them sick to thier stomach. I found it something that I never got used too.
I drove an Eldorado that was either a 1971/72, it was a convertible but what I remember was it had a serious set of BALLz when you pushed down on the pedal..... lmao, I used the car in 1979-80 when I was 18yrs & I'm chuckling at how easy that car slung gravel as you spun doughnuts >> >> she was a gas guzzling bitch of a beast that was fun to drive. You just laid yourself in that car & it enveloped you, it felt so well made/solid yet refined -n- smooth but she was the epitome of all that was Power/Torque ! She was so smooth & would cruise w/o any effort at 100-115mph like a boat on a sea of glass & I'm not exaggerating the feel of that big long hooded masterpiece of a car. I miss that in a car even though I only used one for 3 months, thereabouts. Thank you for the walk down memory lane...... peace & GB ALL
@@puffkendrick6850 >> thanks for the lesson, I only thought about after this video & it was that unique of a car and I've been driving 45 years. I'd call it a "beast" by comparison of all the others I've driven & I'd gladly pay the money for gas if I could drive one again. Thanks for the memories..... peace
WoW, that's very kind.... if you let me know what part of the US you'll expect to Show in, I'll see about making it out? I thought I'd seen you say something like that in here but I got in a hurry & hadn't got back to see if I read it righ?. Yeah, that would be way cool for an old guy like me. peace
Torque was the name of the game on them engines.....working/pulling down low with eas was it,s happy spot and did so well.....as long as you had the gas can ready..I first learnt engines like these and even today I Like my Big Block Chevy engines in a good size car/truck for that reason.....but those early G.M.C. v-6 and big v-8,s was ALL about the load down low...Nice Video man.
Virtually unknown? No kidding, I've never heard of it! I just did the math... 10.5 liters, or just under six times the displacement of my daily driver Toyota. Hmm... I wonder if I can make that swap!
Really great and informative video, Adam. I know so little about GMC products, and I suspect many other people who consider themselves car guys are the same way. Your presentation got me thinking about GMC big trucks. Are they even made anymore? I don't know. I used to see big new GMC commercial trucks often as a kid, but not in many decades, it seems.
sound files for unique engine geometry are a big plus in my mind - but are best when you can find a drive-by with some load on the engine. (the VW W8 of 20 years ago really had me going, back then)
@@markbrodie48 no, I definitely meant the 2002-2004 VW Passat W8 - a 4.0L 8 cylinder engine, formed from two VR4s 72deg apart. The Audi / Bentley / VW Phaeton W12 is exactly the same thing though, 6.0L. The Passat was not a commercial success, because it had almost none of the external trappings of prestige that would have gone along with its internal complexity. You can find RU-vid videos of tearing apart a W8.
Back years ago I owned several trucks of that (and earlier) eras, powered by, among others, a GMC 503 inline six, a Mack 707 inline six, several Fords including a 332 Y-block, a 477V8, and still own to this day a 391 V8 in an F800. All of these engines had their good and bad points but the one that stood, no, towered, head and shoulders above the rest was the GMC 478V6. All of the engines mentioned made good power and, to varying degrees, loved gas (the Mack would get 1MPG if you were on a good downgrade). But also those engines all were sloths when it came to acceleration. Not so the 478. That thing could make a 15,000 pound empty weight truck accelerate like a quick passenger car and it didn't really matter if it was loaded or empty. And for what it was, it was even fairly good on gas. The engines did have their quirks and stupid design elements though. The worst for me was, there were as I recall two short water hoses that connected the front of the block to the water pump housing. I have no idea what, if anything, they were thinking when they came up with that idea, because if the hoses failed, as mine did, I saw no way short of pulling the front cover to replace them. So as a consequence I got used to applying copious amounts of tape to the hoses to keep them alive. But man what an absolute beast for power. As to the subject engine,, the 637, they must have not been very popular in my area as I only ever saw one, and it was in a repair shop for some reason. Back then the heaviest applications in the area were the steel haulers, and most of them (who were still running gassers) were running the 702 twin six.
Forgot to add a correction: GMC always had their own engines, from the smallest to the largest. They did NOT borrow engines from Pontiac! Those engines were a combined effort of Pontiac and GMC. If memory serves the design work was done mostly at Pontiac and the actual nuts and bolts stuff was done across town at the GMC facility, which had the facilities, including dyno cells, to do that work. Yes this all changed in the '60's but until then, GMC was on its own.
Ford produced Super Duty truck engines from 1958-1981 and they had 477 and 534 ci versions, so technically that's the largest on the road gas V8 that Ford ever produced. Well.....unless you count Sherman tanks, which did also technically run on the US streets from time to time. And those pack a 1100 cubic inch all aluminum GAA or GAF Ford V8 motor.
The supply house I work for is getting ready to scrap a 2008 GMC Kodiak with an 8.1 liter gas V-8 motor. It has about 200,000 miles on it and runs great. The transmission has approximately 75,000 miles on it and works great but the truck is too old, rusty and beat up to be a feasible company vehicle. I was thinking of trying to save the motor and trans combo out of it before they get rare.
The GMC big V6 was one of the very best pickup engines ever made (for work). Basically a medium duty engine in those light duty trucks. If it could be somewhat modernized/had aftermarket support, these would be a serious force to be reckoned with. They already were at the time, but few know it. The big cube examples are where it's at - the 351 and below are just as indestructible, but low on power. Shame they didn't keep the 637 around longer too.
the 1980s-90s Nissan V6 (sohc, 2-valve) had its spark plugs inside the cylinder banks - a huge help in doing a tune up on a transverse-engine FWD car. We had a Quest - dependable in the important stuff, but it had developed the longest list of stupid little problems not worth fixing, by the time it was 11 years old and it got totaled, of any car I've ever owned.
@@JTA1961 Yes, but I lead a charmed life, so the accident was not at all my fault, and actually witnessed occurring in real time by a cop. Seeing a puddle, he was about to call a tow truck, but I did a sniff test and realized we could make it a few miles without windshield washer fluid. The crank pulley was rubbing a little on the bent frame, but the Quest got us home safely and to the body shop to meet its end, 129128 on the odometer.
My father had a 63' GMC Stepside with one of those 305cu sixes in it, they had added a T10 4spd.to it, and it Pulled Like Dozer and was Whisper Quiet, and Smooth, but Awful on Fuel. I thought the Plaid valve covers were Cool Too.👍😁
1:33 Ford made an 1100 cubic inch gas v8 for the sherman tank. The "GAA" It had 3 carbs, dual overhead gear driven cams, a cast aluminum block and made 500hp, reved to 3600rpm before valve float. It was a cut down version of a supercharged 60 degree V12 aircraft engine Ford had designed with the hope of selling to the army air corps but they already had the Allison 1710. So when the army asked for engines for sherman tanks, Ford stepped in with a 60 degree flatplane crank V8 monster.
RE: spark plug wires GM did not think the spark plug wires would get "crispy" with the exhaust. The reason for the location was that the Diesel versions of the engine were co-designed with the gasoline versions. It's quit the exaggeration to say the Diesel engines are "converted gasoline engines" when they are instead two engines that were designed with similar manufacturing parameters. In this case, the Diesel engines had the fuel pump and fuel lines distributing pressured fuel to the injectors in the V of the engine, so the intake manifolds were outboard of the cylinder heads. As a compromise, this resulted in the gasoline engines needing spark plugs on the inside of the engine V, meaning spark plugs were installed where Diesel fuel injectors would be.
For US companies , it sounds crazy but they should just bring back the 3800 v6 for all gm and Ford should bring the 300 inline 6. Bbith of them are capable of 450 hp and loads of torque. Oh yeah dodge can kick rocks.
The 8V92 Detroit Diesel which was manufactured by general motors at the time is bigger than this, at 92CI per cylinder it displaced 736CI And yes it was used in trucks so it was a legitimate on the road engine.
Detroit's 12V71 had more CID than thier 8V92. Also Cummins had on-road diesels over 1,000 Cubic Inches. Mack had a V8 diesel that made big cubic inches as well.
@@johneckert1365 Yes I'm aware of that, the scope of this video was GM's biggest displacement V8 on road engine, that would be the Detroit diesel 8V92.
If memory serves, correct both the blue oval, and the pentastar team also had a larger than passenger car gasoline powered V8s for industrial use in that era as well. Ford had a 534SD, and Dodge had an available 478. However, Dodge used an International Harvester built unit.
The “biggest” V8 I know of is the 903 Cummins that was used in trucks and equipment from the mid 70s. They earned the nickname 9 oh nothin since they were such a boat anchor.
Speaking of larger engines, in Popular Mecanics magazine sometime in 1978 there was an article about a Ford LTD with a 553 CID engine. I have never seen or heard anything about that engine again.
