deant54,
Look for a 54 Chevy 1/2 ton frame, they are out there. Several years ago I needed one for my 54 3100 (mine was very badly rusted), and found one from a Bolter here. The frame was in Oklahoma, the price was good, and I found someone that would bring it to northern Florida very reasonably, where I was able to pick it up. You'll have a lot less problems and it will be an easy swap, since the 54 1/2 ton frames are different from the earlier AD 1/2 ton frames.
Samantha