Hi Hemi 5.7 cuda,
You may want to check out
www.moparts.com/Tech/Archive/rearsusp/12.html and
then link to the Doctor Diff site for what looks like a pretty stout 1 inch relocate kit.
I think it looks stronger than the Mop Perf piece and puts the springs over the full one inch
instead of the 3/4 inch that the Mop Perf does. Some guys have gotten away with forcing
the spring over the extra 1/4 inch to fit the (pre 1970)b -body rear while using the Mop Perf
kit. I think the Doc Diff setup puts it right where it needs to be if you go the b-bod rear route.
Jeff