10 inch rear drum brakes

Can someone take the time to answer this question. Am in the process of trying to convert 7.25 rear end SBP 9 in. drums to BBP 10 in. drums for 8.75 rear end. Question is what years will suit my needs. Looking for 10 in BBP 10 X 2.5 backing plates. Is backing plate for 10 X 2.5 SBP different than 10 X 2.5 BBP?