Small Bolt Drums

Tims 66 Cuda said
You might also see if a B body car had a similar drum

Bolt pattern and back spacing mismatch.

Your rear brakes might be 10x1.75 but later years used 10 x 2.5 (IIRC) all with SBP 5x4

This is all assuming that the rear is an OEM A body housing and axles