7 1/4 to 8 3/4 swap question about brakes

See I have this 71 Dart and its getting a 440 whether it likes it or not. I also have this 8 3/4 that I plan to put in with it. My question is. Can I use the backing plates and drums from the 7 1/4 on the 8 3/4. Both rears are SBP.