Interesting question. I don't know the answer to what you're really asking, but suspect there is no change in the sheet metal and you could easily put a '53 and earlier panel or Suburban on a '54-'55 1st frame.
And you could likely go the other way too.
You can put a '53 and earlier bed on the later frame, but not a '54-55 1st bed on an early frame.
If you follow this link and dig around a bit you may be able to figure it out.
Resto Packs OnlineMy asnwer would be that the '54-'55 1st frames for 1/2-tons Chevys are all the same and only the attached body mounts are actually different. Both a pickup and panel frame will have all the same holes drilled for the mounts.
But did they modify the body to lower the deck? The doors are the same and the inner fenders appear the same, but this isn't something I've ever measured.
I now wonder if the panel/Suburban body mounts are different for the two frames. You can look that up on the same site if you have to know. I don't care enough to do it tonight for sure.
I have both a '53 and a '55 1st Suburban at home but have no idea when I could try to measure them. Doing so is more complicated than just running a tape from the ground to the rear deck because of tire sizes and sagging springs and such.
