VCCA Home Forums GENERAL DISCUSSION General Discussions Side valve inline 8 cylinder

Did GM produce a side valve inline 8 cylinder engine and what cars was it fitted. It has GM1 cast near the rear spark plug.
Tony

pontiac

Pontiac and Oldsmobile used flat head engines. Also remember Cadillac had some flat head V-8s not sure about inline?

Both Pontiac and Oldsmobile had side valve straight 8 engines. The engines were simular but not the same. The Pontiac engine usually had the Chief Pontiac Indian head and circle on the left side of the block. The numbers you have listed are not enough to ID either engine.
If you can send me pictures of the engine I could ID it for you.

Cadillac used the Olds flathead straight eight in the '34 through '36 LaSalles, though the LaSalle engine was assembled by the Cadillac division and had some modifications and improvements over the stock Oldsmobile unit.

Thank you for the information
It is in a box at the moment so pics will be almost impossible. It is a customers unit that has been brought in for reconditioning machine work and is now all packed up ready for pick up.
I really only posted out of curiosity as I had not previously heard of a GM flat head inline 8.
Tony

I did not get a chance to look any closer at the engine but did find out it came out of a Plymouth which I realize is not a GM product.
Tony

If its an eight cylinder it would not be a Plymouth. Then it would be a Chrysler, 1950 and prior, or a Dodge or DeSoto, 1931-1933.

I knew Pontiac, Cadilac and Oldsmobile all coming from under the GM roof and possibly Buik shared parts but Plymouth, Chrysler and DeSoto from under the Dodge roof would hardly carry the GM brand.
Tony

Wonder if the GM1 mark is just a casting or cavity mark. Like General Machine made the master and number 1 master used for this engine block. GM used cavity id on their major castings to identify when a master needed work.

Or another possibility is that Saginaw Foundry or other GM facility poured some blocks for Chrysler.

i just went up to the barn and checked for casting #'s on our 32 Dodge 4 dr sedan with original flathead 8 cyl inline engine. there are no GM casting #'s on the block or head. there is a machined engine stamp pad on the drivers side of the block, about an inch below the head/block mating surfaces, and its located up front between the first and third head stud/nut. mike

This had GM1 cast in the rear of head reading from left side, the engine # (dont remember what it is) stamped on head gasket face I think left rear corner. I didnt get a chance to have a good look at it though.
Tony