8 3/4 Big bolt Conversion axles. What Backing Plates?

Hey, I am converting my 76 Duster's rear end to an 8 3/4 from the original 8 1/4. All I have for the 8 3/4 is the housing, and plan on getting the large bolt pattern conversion axles for it. I have read and been told to get B or E body backing plates and brakes for it. The question I have is, will the backing plates and brakes from my 8 1/4 work/fit? or No? They are 10". I would like to be able to use them so I do not have to find and buy another set. Any help would be great. Thanks.