This is a pretty good place to find compatibility. The frames are differant between the 48 and the 54. The main differance is the bed mounts, a 48 bed will not fit on a 54 frame and vise versa without serious modifications. The '54 frame is much flatter than previous ones and the bed mounts completely differantly. However, any stepside bed up into the 1970's will fit on a '54 frame, so you should be able to find another pretty easily. Someone else here will post cab info. I think the '48 cabs had a differant frame mount from the '49-54. However, I wouldn't pass up the chance to get a good parts truck, you can always trade around for parts for someone who might be in the exact opposite situation than you, trying to fix up a '48 with '54 parts.
