What are the differences between GMC and Chevy AD frames?

[MrTucker]

I have a 1953 GMC 1/2 ton long bed with a slightly twisted frame. I've read on Stovebolt and OldGMCTrucks and I know that there are differences between GMC and Chevy frames - specifically in the radiator support area to compensate for the longer/larger GMC motor. What other differences are there?

I'm not planning on keeping the original drive train, instead I'm going with a sbc/th400/MII set up.

I also have a line on a super cheap Chevy shortbed 1/2 ton frame that I wouldn't mind picking up - if it will work.

thoughts??