AD frame rails 1/2 ton '48-'53 are the same. The "54 1/2 ton frame is slightly different, but the front part is the same.
3/4 ton frame is entirely different and so is the 1 ton frame.
So you have 3 different frames, in width, length, frame rail height, rear spring mounts, area over the rear axle etc. Cab mounts are totally different on the '48 also.
