The Stovebolt Site Forums The Shop Area The HiPo Shop 47 thru 54 frame difference

I am about to start the swap of a 95 350 into my '54 3100. As I start finding information in the forums for best engine mounts, engine location and such on '47 thru '54 3100's, I am trying to learn if there are frame differences in the engine bay I should be aware of, or are all 47-54 dimensions the same?

Chevy and GMC front crossmembers are different where the front engine mount for the 6-cyl and the radiator support mount. That's the only engine bay difference I can think of. Out back the 54 frame rise over the rear axle is lower than on the 47-53.

There were a few other differences in 1954 frames:
- the cross member at the rear of the engine changed significantly
- that change allowed the elimination of a frame cross-member at the rear of the transmission
- a few other changes are described on several pages at the link below

http://www.1954advance-design.com/Documents/EngineeringFeatures/slides/orig_Page50.html

http://www.jimcartertruckparts.com/Articles/Chevy-and-GMC-Frames.php

https://www.oldchevytrucks.com/blog...-articles/1947-55/frame-chassis-1947-55/

The 47-53 3100 trucks had a really high arch above the rear axle. The 54 and 55.1, not much arch at all.

The 3600 trucks for all years had basically the same kick up as the 54 & 55.1. 3800 and larger trucks had a flat frame.

54-59 trucks had as mentioned earlier a different center crossmember. It enables you to use early v8 style bellhousings for doing engine swaps. You have to use front motor mounts though. Most just hack them out and use side mounts and a rear trans mount.

Thanks everyone--- I may be getting a little ahead of myself. After I get the 6 cyl. out, and the front end off, I'll just let the 350engine and 350 automatic hang from the hoist into the engine bay and get the lay of things. You can bet I'll have lots more questions when I reach that point.

OK -- now I realize that there are kits that make the swap a lot simpler. The one that has been most recommended to me is the Chassis Engineering kit. However, I see they have been bought out by Heidt's and are not up to speed yet on offering this kit. Is it worth waiting for, or are other kits just as good and just as easy to install?

Chevs of the Forties appears to carry Chassis Engineering's kit. They may or may not have them in stock. Worth a look. Part # CP-1160
Carl

Just let the engine and tranny hang from the lift in the engine bay area to see how it looked. I was also wondering if I could leave the stock, rear engine cross member in place for added frame strength. I'm sure Y'all could have TOLD me it would have to come out for the V-8. It looks like even after I remove all the rivets, it's a tight enough fit that I'll have to cut it into to get it out.

That rear engine crossmember is right behind the spring perches of the front leaf springs, so yes you need something there for support. You may be able to leave it alone as is without interference. The problem with that route is that once the truck is all together you wouldn't be able to drop the transmission. I learned that the hard way. Its too close to the transmission for my tastes anyway, so I out the center of it, fabricated some drop brackets, lowering it 2 inches so that I could bolt everything together for easy access to the transmission.