72 Duster Rear Axle

Welcome to FABO! I agree with rob robinson87.....8 3/4 would be my first choice (either bolt pattern) and 8 1/4 would be second choice if you're swapping to the big bolt pattern wheels. This is assuming you want to just bolt one in without having to make it fit. If you can't find an A-body rear, do what daredevil suggests on a B-body rear or get a C-body (or other vehicle) and have it narrowed and good axles made for it.