The Stovebolt Site Forums The Shop Area Driveline AD Frame Question

I’ve got a stock 1955 1st Series Chevy 3100 series truck and the rear half of the original frame is in very poor shape due to corrosion and everyday use. I’m considering trying to find another original AD frame in better shape that would accept my 55 cab and bed without modifications. The 55 1st series was the first year for the open drive shaft. Are there other AD frames from earlier years (pre-55) that are directly compatible with the mounting points for my 55 1st Series cab and bed? Thanks.

I believe you could mount your cab on any year AD frame, but the bed would only fit on a 54 or 55.1 frame, as the earlier frames have a higher hump over the rear axle. I believe, but can't be 100% sure that the rear springs and mount points would interchange between a 54 with torque tube rear axle and a 55.1 open driveshaft axle.
[on edit] I just checked with Eaton Detroit Springs website and 55.1 springs are different than earlier AD, but if you already have the springs, all that's needed is for the mounting points to be the same. 54 rear springs are 8-leaf, 54 inches long, while 55.1 springs are 8 leaf, 54-1/8 inches long, per the vehicle info kit data. That's probably an inconsequential difference. The mounting point center-center dimension difference is about 1/4 inch, again probably workable.

Thank you