Rear drums rubbing

Couple of possible issues-

1: You can't mix and match parts from the 10x1.75" brakes and the 10x2.5" brakes. Which also means, you can't use the 10x1.75" backing plates with BBP axles and the 10x2.5" brake set up. If you re-used your backing plates, that's the problem.

2: Moser sells axles that use the small bolt pattern axle flange offset, but that have the large 5x4.5" bolt pattern. Those axles are intended to be used with the 10x1.75" brakes, with the new 5x4.5" bolt pattern needing to be drilled on the OLD drums. They can not be used with the 10x2.5" brakes, because the axle flange offset is different between the SBP and BBP axles.