The Stovebolt Site Forums The Parking Lot Big Bolts Biggest 6-Cylinder Engine?

We are talking on another board about big 6's in the early to mid 50's heavy Chevy and GMC trucks. What were some of the big cube engines back then? I tried doing some research on it, but it is a little hard to find for some reason.

Bill

Biggest thing I can think of off the top of my head was the 261 inline 6 in some of the task force trucks. But I am no expert by any means.

Not Chevy or GMC,
But Hall-Scott made some really big ones.
I've got a manual here in front of me for a "Hudson Invader 168" marine engine, which was a Hall-Scott design made by Hudson during the war.
The same basic Hall-Scott engine was also a truck engine.
The marine version is 997.8 cubic inches and 250 hp at 2100 rpm.

The truck engine eventually evolved into a 1,090.6 cubic inch with a larger bore of 5.75" and the same stroke of 7".
This engine was in the Pacific M26 "Dragon Wagon" among other things.

A great article in the January/February 2005 wheels of Time about Hall-Scott.

Or do you intend to limit this discussion to only GM engines?

Grigg

503 GMC

302 GMC is a superb engine.

292 Chevrolet (and GMC)

270 GMC

261 Chevrolet

IF GM only,
Then my 49-53 model 400-980 parts manual list the 503 gas engine as the largest. And the 6-71 Diesel was used in the biggest of the trucks.

Grigg,

Appreciate the info on Hall-Scott. Interesting info that I never knew, but 503 was what I was looking for. I thought I remembered something like a 501, but I see now it is a 503.

Appreciate all the replies.

Bill

One more question, could you get the GMC 503 in a Chevy and if not, what was the biggest in a Chevy?

Bill

Biggest Chevy 6 in that time is 261.
Export trucks may have exceptions.
In the 50's Chevy didn't have a big enough truck for the big GMC gas engines any how.

Grigg

P.S. speaking of big 6's, at the moment your post count is 478, know what engine that is?

Thanks Grigg, was the 261 powerful enough for a medium size tractor hauling a trailer load of 4 new cars.

(That's the conversation we're having on the other board).

Bill

Sure do. I drove a 478 V-6 in a '62 GMC 6500 for 3 years. It was a monster engine in a monster truck for the time.

Bill

My opinion,
No, probably not..

Did they actually do it though?
Probably did, and I bet they had an auxiliary transmission.

I went to the picture collection page and found the truck that we are talking about:

http://www.hankstruckpictures.com/pix/trucks/john_jurkowski/2004/apr/12/trucks/scan0025jj6.jpg

Someone thought this truck could have a Detroit in it, but it was my opinion that it had a 6-Cylinder gas. Would you agree that this truck most likely had a 261?

Bill

I just drove a 1970 Chevrolet T-80 with a 478 V6 home three weeks ago...820 miles . I got 6.9 mpg with a top speed of 58 mph at 3000 rpm.

Mike B

The truck in the picture appears to be about a 1950 model. 235 was Chev's biggest offering for that year. The 261 did not appear until 1954. A 235 would pull a single axle trailer...just not very fast. That's why drivers drove day and night to get somewhere and many of them bounced pills off the windshield to stay awake.

That's pretty close to the '62 478 that I used to drive. The top speed on that truck was 62. As mentioned just recently, we always thought that truck got about 7 to 9. If you super tune the engine and make sure it has straight thru mufflers, you should do better on the mileage. Does it have straight thru duals now?

Thanks. Would that be a high pressure engine or the old babbit type?

Looks like a 49 or 50 2 ton. And another (conventional) one in the background.
Should have been a gas engine.
And a splash oil 235 right?

Hopefully Tim will come along and set us all straight.

Grigg

There was also a 707ci. GMC 6 cyl. gas engine,first available in 1950.

The GMC motors were not offered in Chevy trucks at the same, though GMC did market it's motors to upgrade other trucks. Somewhere I have a copy of a letter from GMC to dealers telling just how to sell GMC motors for use in other brands.

The biggest GMC motor I've seen installed in a Chevy would be the 302. It does require some modification but is a reasonable swap.

503? 707??? Geeeez that's some cubes there! I've been thinkin if I were to upgrade my engine in the dump I'd go for a 302 since there's a some good performance parts out there. 302 seemed more common than my 270 was.

ANYway,... I can see a 2-something hundred cubic inch engine moving that much steel, no problem at all. Stopping might be fun tho!
It's not the size of the engine that matters so much as the gears. Seemed like back in the bad 'ol days ya have two choices, payload or speed, but ya cant have both!

While I was searching around, I did see something about a 707, but it was hard to believe.

I also read some interesting info about GMC back in the old days. There was some pretty impressive stuff. GM even won an award from the US Government for their contributions in WWII.

Read more here, along with some pretty good pictures:
http://wiki.gmnext.com/wiki/index.php/A_Brief_Outline_of_the_First_Century_of_GMC_Truck_History


Bill

Late 1949 or 1950.
- hood side-emblems changed to two pieces in late-49
- door vent-windows started in 1951

The COEs most likely came standard with a 235 (low pressure) engine. A 1949 235 would have produced 93 hp and a 1950 235 would have produced 105 hp (due to larger intake/exhaust ports and larger valves).

International made a 501 Gas 6 cylinder.

"International made a 501 Gas 6 cylinder."

Wasn't that the one they called the Black Diamond? I also recall a Red Diamond IH engine.

I think that your correct Dave. I had a old IHC semi tractor and it had the 450 6 cylinder which I recall to have been called a Super Red Diamond. Don

The 707 was from back in the 30's. I'm not sure it was still available in 1950. I have only seen one in my life. It had a direct coupled air compressor and two spark plugs per cylinder. It was about the same size as the 855 block Cummins Diesel used for about 50 years. Fully dressed, a Cummins weights close to 4,000 lbs and were only used in the largest conventional cabs. A 302 was the largest engine that was feasible to retrofit into a Chev of the era pictured. However the 302 wasn't released until 1952. The International captured a large portion of the market in its class with the RD450 in the R190 series truck which was introduced in 1954.

I don't know if it's the same engine as crenwelge has mentioned, but i'm looking at a catalog titled, "GMC Heavy Duty Trucks- Gasoline-diesel", published 5/1949 that list a group of engines as new for 1950, & they are a 318, 360, 426, 503, & 707.

I think Mack had a 707ci six in the 50s also, just a coincidence?

My 49-53 GMC truck master parts book number X-152002 (covers model 400-980) makes no mention of the 707 in the engine section, 503 is as big as it list.

Was there an even larger truck that would have used the 707?
Or did the catalog predict an engine that wasn't available after all?

Grigg

Look at 1933 and 1936.


from Coachbuilt.com (707 used in Yellow Cab Co. bus - bought by GMC )

"Greyhound, the dominant U.S. intercity bus operator, arranged to sell its wholly owned bus manufacturing subsidiary C.H. Will Motors Corp. (see Will) to Yellow Coach during 1929, and Yellow subsequently designed and built a 250-inch-wheelbase Type Z parlor coach chassis to Greyhound specifications. This type of bus was the last con­ventional Yellow chassis to be introduced, as work was al. ready under way on new designs that enclosed the engine within the body. The big Z-250 used a 707-cubic-inch six­-cylinder engine, while smaller Yellows were equipped with either 616 or 568-cubic-inch motors. After 1930, GM Truck engines were used in the smallest models in place of the earlier Cadillac or Buick automobile engines.

Between 1931 and 1934, Yellow built and sold a small number of city transit buses with rear-mounted engines that drove forward. These were not particularly success­ful, the largest types encountering 'significant clutch trouble because the largest engine that could be accommodated within the bus was too small for the size of the ve­hicle. In the meantime the small types U and W were superseded by front-engine forward-control buses.

The use of letter designations was given up, and buses (and a few trolley-coaches) of the new designs were labeled with model numbers in the 700 series. Production of types V and Z, especially the parlor versions, continued until 1936."

There is a possibility that a 707 was still available later for fire apparatus. Back in the 50's, as now fire insurance is rated by the fire equipment available. Insurance companies gave low ratings to Diesel powered equipment because it wouldn't start in cold weather in those days. They also had guidelines as far as displacement for different gpm pumpers. There was a category that required a 700 cu in engine which made the 707 Mack a popular engine for fire apparatus. The 5" bore 6" stroke Mack was a very durable work horse, but I don't think it had anything to do with GMC. It could have been that GMC still produced the 707 for fire trucks, but they really pushed the 71 series Diesels in their highway offerings because they owned Detroit.

When I was a kid, we had a '47 to '55 1st Design style GMC fire truck at our local station house. I don't know much about badging on those old trucks, but it was either the heaviest style or one below it. It had "GENERAL" on the front of the hood. It was a gas engine and it had a very distintive sound to it. I could tell what was coming down the road before they even got the siren going. I'm wondering now if that was a 503 or possibly a 707. Anyone know of any sites with sounds of those old monsters?

Bill

I wonder what the truck in the photo, loaded as it was, would do on a flat highway. I am guessing that it would have had a governor on it, correct?

Much like the old straight 8's (a duesenberg 8 with crank mounted super charger,... *sigh*), I'd love to get ahold of a 707-6. That sounds too cool, even if it was just on a display stand it would be an interesting piece of machinery to tinker on.
Still doesn't carry the monster quality of the GMC V-12, (something else I'd love to have), but that's still a huge engine!

Funny thing is, the 707-6 actually has 5 more Cubic Inches than the V-12 has. I can just imagine what a piston looks like out of a 707.

Bill

The pistons are not as big as you might think. When you figure displacement you multiply the radius squared times PI times the stroke. When you square the radius it gets up there in a hurry. But they were heavy. I would imagine the red line was probably around 2200 rpm.

Talk about size, the 707 is large, especially for a gas engine. It works out to be approx. 118 cubic inches per hole. Diesels, on the other hand, are often much larger. The commonly used 6 cylinder NH Cummins Diesels from the early 60's onward were 855 cubic inches, which is over 142 CID per hole. They provided horsepower ratings of 220 on up to 400 hp. (maybe more!) I've seen their pistons and they are quite massive, I still have a few NH pistons around the shop today. The Cat 3406 6 cylinders were even larger.

James

Hey Bill, I have a 54 630 series General firetruck. It has the 503. GMC had a special wheelbase chassis for the firetrucks and was marketed as such. 503, 5 speed trans and 6.50 geared rear (mine came with a detroit locker). I have searched youtube and such but with no luck, heck even finding info on the 503 is a struggle. I think the 707 might have come in an off road type truck with an extended hood like an FWD.

peytonmaterne,

Sounds like you've got a nice truck.

If you ever get any pictures of it, I would like to compare it (by memory) to the firetruck we had in our neighborhood.

Bill