47-55.1 GMC ? Chevrolet 235 difference

[Jurassic-1]

Does anyone know if a 1954-1955 1st series 235 is longer in a GMC than in a Chevrolet?

[joedoh]

answering your exact question, a chevrolet 235 will be the same length no matter what truck its installed in :P


but jokes aside, gmc engines are completely different than chevrolets, and yes they are about an inch longer. gmc didnt make a 235, they made a 228, 248, and 270. in a half ton 54-55.1 it should be a 248. you can find the engine size on the flat pad next to the distributor, the first 3 numbers will be the engine size.

gmc engines were full pressure oilers (so were the 235 chevys of 54-55 though) and made more torque.

[whitedog76]

GMC I6 engines are actually longer than the Chevy.

On the early trucks there was a dip in the front crossmember on the GMCs so the front pulley would clear the radiator support.

[Jurassic-1]

Thank You for the info. Seems there were a lot of differences in those days. Today just looks.

[mr48chev]

Yep, the old timers (way older than me) still will tell you that the GMC trucks from those years were built a lot more heavy duty than a Chevy was. Frame is exactly the same except for the front crossmember but I have probably had a hundred guys who would now be in their 90's tell me that the GMC trucks were built more heavy duty.

Back when I was 19 I put a 248 GMC six in a 50 Chevy hardtop and that was quite a challenge. It would have been a lot easier to replace the broken piston in the 216 and do a ring and valve job.

[mr48chev]

The top photo is (or should be) a member's truck showing the Jag XJ suspension install that shows the Chevy front crossmember

The other photo is a shot of the front of my GMC 1/2 longbed frame that I am going to use under my 48 in the rebuild. I'm using it so I can stretch the cab 9-1/4 inches and have an unmodified frame.

You can see the way the front crossmember is dipped way down where the core support sits.

[Jurassic-1]

I have several projects of my own. I have a friend who has this 54-55 GMC . He may need a rebuild able GMC engine. I passed the information everyone passed on about the size. Any leads on another engine would be appreciated. I have a 1955 1St series 3100 Chevrolet 5 window in my collection. It has 67000 actual miles on it. It has a hydro attic trans in it. It runs great.

[whitedog76]

The Chevy engine will fit a GMC, you just need to keep the GMC radiator support.

The Chevy car engines have the longer water pump, which causes some clearance issues, but since yours is from a 54-55 1st series, shouldn’t be an issue.

[whateverpratt]

I think the reason the old timers talk about how the GMC trucks were more heavy duty must be that the GMC range went beyond the 2 ton weight rating that chevy stopped at until the '60's or so when chevy started making some really heavy trucks.