The Stovebolt Site Forums The Parking Lot Big Bolts 49 GMC,48 Chevy engine ???

I have a 49 GMC 1 1/2 ton,and have come across a 48 Chevy 1 1/2 ton.I know they have different engines,but would the engine out of the 48 Chevy bolt into my 49 GMC? Or not.All I am missing is the engine,and had thought about installing a SBC,but if the 6 will bolt in,that would work too.

The Chevy engine is a little shorter. It has been done thousands of times. It my opinion it screws up a good GMC. I'd try to find a GMC 6 if it were mine.

I would like to keep it all GMC.But at least with a Chevy,it will stay in the family.Now,if I said I was going to put a Ford in it,I would expect someone to personally shoot me!!! I still need to know,if it is a bolt in.Will it bolt right in like the original engine,with no modifications? And what would be some of the options be as far as the original engine,216,235?

The original would have been a 228 or 248. Chebby engines then would have been the 216.5 or the low-pressure (POS) 235. Stay GMC - the engines are far better constructed than the Chebby powerplants.

Unless the Chebby motor has been switched, it's a low-pressure babbit-bearing motor, and I'd avoid it like the plague.

What's the real deal on the 235 low pressure vice high pressure 235?

I've got an old low pressure 235 from 1951 with only 20,000 miles on it. It works great but wonder if I should be looking for a high pressure 235. The dash oil gage used to read 30max on the old six volt set up dash cluster but when I got the new one rebuilt by Chevy Duty it is now set to read 60 max. Does it really make any difference? How come and what is the difference between the engines?

You get a little better lubrication with the full presure engines. Since your engine has been maintained and is rumnning well there's no need to worry about finding a full pressure enginne. GMC's and full pressure chevys had the 60lb gauges.Poeple ran the lowpresure engines for years with little problem, evidence your fire truck.

No it won't. As I said earlier, the Chevy engine is shorter so you'll have to booger up the front crossmember to rig up a front motor mount. :rolleyes:

firetruck, if the old 235 is running fine, leave it alone. If it blows up, I'd look into a later full-pressure engine.

I wonder how much shorter the Chevy motor is and whether or not this causes issues with the fan being to far away from the rad.

Also if you are going to a totally different motor, one of the larger GMCs could give you quite a boost in power. That would save all the problems with installing a V8.

Thanks. It runs great so far without a problem. I hope it lasts!

Thanks for all the info.I have had no luck finding a GMC engine.But a local wrecking yard,about the only one left with the old good stuff has a pretty much complete 48 1.5 ton.When I saw the engine,I thought it might work.But I may just end up going SBC.The extra ponies might be nice.Did'nt GMC have a V8 in some of their later trucks?Would it bolt up to the SM420 4spd? I came across a SM420 also that had a huge bellhousing bolted to it,and assumed it was for a GMC.

No V8s in any GM truck before the 1955 second series. With an SBC you have to look out for the steering system. Check out the page in my signature - they might be able to help out your engine situation, seeing as you're out there on the left coast.