8.5 rear end

Your car originally came with a 7 1/4" Chrysler rear axle. Some of the A-bodies, typically with V8 4-bbl engines and some towing packages, came with a Chrysler 8 3/4" axles. So the most straightforward swap is a Chrysler 8 3/4" that came out of another A-body. You could have one of the 8 3/4" units and the pumpkin does come out on the drive-shaft side. Or some one could have put a brand X in it too. Pics would really help.