A-904+rear end, HP ratings

8 3/4 came in 67-72 A-bodies Duster/Dart/Demon/Cuda 4inch bolt pattern SBP
8 1/4 came in 73-76 Dart Sport/Duster basically anything with V8 4 1/2 inch bolt pattern..LBP

I don,t think a wagon rear will bolt in an a-body unless it was from an Early-A v8 car,which would be rare.Hope this helps