Hey gents, got a quick technical question. My dads 55 GMC pickup at some point was converted from the 248 to a chevy 235 with manual transmission. We have been searching for a 248, 270, or 302 to get a GMC motor back into it. We have a lead on a 270 with or without the 3 speed manual. My question is, does the 270 and 235 share the same manual transmission, or do I need to get the 3 speed with the 270? Also, the 270 has an air filter without oil bath. My dads truck is all original for the most part. Does a 55 1st series GMC have an oil bath or a regular oil filter? When did the inline-six GMC or chevy convert away from oil bath filters? Is the oil bath filter on the 235 likely compatible with the carb on the 270? Thanks for your help
I think they used oil bath air filters on Chevy six pickups all thru the 235 years. GMC used them in the mid 60s on the V6, I don't know about the 270, but I would be surprised if it was a dry filter. The back of a GMC 270 will bolt to a Chevy 235 bellhousing. I think the flywheel is different, but also the transmission should be the same where it bolts to the bellhousing. Check to see if you have a Chevy or GMC bellhousing in the truck? I don't know if Chevy and GMC used the same transmission..how about you look at the truck, and look at the transmission the guy has for sale with the engine, and see if they're the same?
In my 52 GMC pickup, it had the 228 GMC engine and full drivetrain when I got it. The trans is exactly identical to the Chevy trans, and the bellhousing sure looked the same as when compared to a Chevy truck setup my friend had. I gave him the whole drivetrain to use in an old 29-ish Chevy pickup project. The bellhousing bolt pattern is the same GMC 228/248/270/302 six (might be a 256(?) or something in there as well) and Chevy 216/235/261 six. No idea on flywheel or clutch parts, I never separated the engine and trans from the GMC.
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