C body or B body wagon 8 3/4 rear

I am actually looking for this rear for a stepside pickup. According to a Moparts tech article, 71 to 73 B body wagons, 70 to 73 C bodies minus the Imperial, and 72 to 74 trucks share the same dimensions. The only difference may be the pads, but the springs are relocated on my truck and I will have to weld new perches on anyway. I would really like to put a narrowed rear under it, but then the cost starts to add up.