8.75 Rear End Drum Brakes

Sounds like you have a mismatch between your axles and your brakes. SBP axles have a different flange offset than BBP axles-

Yep,... What Blu said. Seems to me, when I talked to Cass at Doctor Diff about changing my '67 Barracuda to big bolt pattern, he told me the same thing and said I'd have to get new brakes because of the axle sticking out further. They sell a 10x2 1/2 brake assembly there (for $350) that comes with the backing plates, drums, and all the hardware. I just checked though and it is showing out of stock. Might check with them and see when they expect them to be back in stock