Converting rear drum brakes from SBP to BBP

Please let me know if my research is correct for the rear end. To install a 8 3/4 my options are:
Find a 8 3/4 from a 65-72 A body then change the axle shafts to BBP and either drill the drums or change backing plates and drums from BBP car.
Find a 62-70 B body rear end and move the spring perch in 1/2" which will require new perch with 1/2" locating pin hole.
Are these my options?