The Stovebolt Site Forums The Shop Area Engine Shop 235 into a '51 GMC

Hi - I'm a new owner of a '51 GMC 1/2 ton that no longer has it's original 216.

I've been guided to add a '55 or later 235 engine, trans, and rear end.

Is this pretty much a bolt in procedure? If not, what tasks or modifications do I need to know about? Thanks - Dickson

Hi - I'm Dickson in Denver and I have a "new" '51 GMC 1/2 ton. It's a pretty solid cab and bed, complete except for missing it's original engine.

I've restored 60's mustangs and 70's Alfa before, but this is my first vintage truck.

I'm thinking of adding a '55 or later engine/trans/rear end.


I plan to repaint, recover seats, and get her back on the road looking good.

Thanks in advance for any help or encouragement! Dickson

51 GMC

Welcome to the Bolt'

A good upgrade would be the 302 GMC six, hard to find and pricey, but a great engine with power. The 270 is a good option. I am in the process of installing a 302 and a 4 speed overdrive, it will have a 1959 rear end with 3:90 gear ratio.

Just to let you know if you aren't aware, the Chevy 235 engines are shorter than the GMC'S.

Old POST on same subject.

GMC Casting Numbers

First a GMC would not have a 216, more likely had a 228 or...
Putting a 235 in is no problem except they are about 1 1/2" shorter so the front engine mount needs adapting.

Personally I would stick with a GMC engine. Preferably a 302, in my opinion, really, really preferably....

It might of had a 216 in it if it were a Canadian truck,than it will be a easy to install the 235.


Pete

Thanks a lot guys. This is why a newbie has to ask!

I'll start looking for a 302...

I would advise another 228 or 248 perhaps. Just don't get caught up in the "bigger is better" mentality or you'll go off course. Understand first what you expect from this truck, why you have it, what level of expertise and dollars you can approach it with. There is absolutely no reason to have a huge engine that was never used in your truck as a replacement for what it was designed and engineered for. Yes, it will fit in the space..but that is only the start of things to come.

The cost to rebuild the engines are about the same, so why not go bigger? More power, and can be made into a performance engine with available parts. He is also located in Colorado, so power would be a good thing for those mountain roads.


REBUILT 228

Cool, a long-wheelbase 1/2-ton. Way to go. Good luck with it. Have fun but be safe.

Is it a Canadian truck? It seems that lots of them ended up in the Lower 48.

Are you sure it's a 1/2 ton. Check your vin on the driver's door cowl. Chevy long beds were not mfg in the USA, only Canada and Australia.

Thanks Frank. I really have no idea about the history of the truck, but I'm excited to work on it and enjoy getting it back on the road.

Don't know Jim. That's what I was told...I'll check the data plates & decode.

It is not a Chevy. Long bed GMCs are common.

Guess I should improve my reading skills.

Dickson,
If you want real bragging rights, you might consider a Cleveland..........but seriously, if it's a GMC stay with a GMC power plant. What are your long term plans for the truck?

I would also look for a GMC 270 or 302, S. N. on starboard side of block, Stamped on machined pad to rear of distr., displacement in first 3 numbers of S. N., i.e. 302xxxx. All GMC's from 228 on look the same, most yards don't know the difference, so just look around yourself.

I wouldn't really consider 302 cubic inches to be "huge" adequate maybe, but not much more. Lets face it, the performance of any of these sixes even under the best circumstances isn't all that earth shattering. Unless you are going with a 12 port head, forced induction of some kind, or something along those lines, that cost lots o'money.

If he was looking for "huge" or "earth shattering" he wouldn't be considering a 235. We don't all race our trucks.

No one is trying to coerce anyone toward any engine as I see it, just talking about what they would do. In my mind it's good education for a rookie in this hobby.

Well put.