Engine replacement: 55 Chevy V8 into a GMC 55 pickup frame

[BillR]

I have a 55 GMC pickup with a 248 6 cylinder engine, 3 on the column, and would like to replace the engine with a 55 Chevy V8 265 engine. Looking for any information on how to set the engine in the 55 GMC frame/motor mounts or any knowledge on the extra holes in the factory motor mount. Was the motor mount made to house either the inline 6 or a V8? Any pieces of knowledge on how to find possible mounts that would work? Looking for a way to use the existing holes in the GMC 248 frame to mount the 55 Chevy engine?

Any knowledge, suggestions, or guidance on where to look would be greatly appreciated.

 

[Bill Hanlon]

I'm assuming your 55 GMC is a 2nd series (looks like a '56) and not a 1st series (looks like a '54).

The motor mounts for the 2nd series GMC engines, both the 248 six cylinder and the 288 or 316 V8, both had a center front mount and side mounts on the bellhousing. Frames are the same from 6 to V8. You will definitely need to install custom mounts for the 265. I wouldn't bet my life on it, but I don't think either GMC bellhousing would bolt to the Chevy block without some kind of adapter.

Just curious, why a 265?

 

[BillR]

I have a 248 GMC 1955 with 3 on the column, had the engine rebuilt 2 years ago, and have had oil leaks ever since, even upon taking back and supposedly being fixed 2 times. Now oil even comes out of the exhaust. Only about 2,000 miles on the engine, doesn't sound right, and over $3,000 into it. I have a 265 V8 motor with overdrive transmission, 3-speed standard taken out of a 55 Chevy, ran well when I parked it over 10-15 years ago. So to answer your question I have the 265 motor on hand, right now sitting in the garage it which I start period and sounds good. (no oil leaks)