8.25's use the exact same 10x2.5" brakes as the BBP 8 3/4's.
As for the OP, you've got mismatched parts. If the drums hit the backing plates you've got the wrong backing plates, drums, or axles somehow. Is this an A-body 8 3/4 housing? Are the axles original? What bolt pattern is on them, and have they been re-drilled? The wheel studs look like they're swimming in some of those holes in the drums. Something's wrong. What size are the wheel studs?
