8 3/4 What are my options?????

If you want to retain the SBP, the easiest thing to do is get a complete 10" 65-72 A-body rear drum setup. All of it. I'm pretty sure the 10" strut bars are all the same but an 11" is different. The shoes will be 10" x 1-3/4", standard a-body size for those years. Backing plates are a direct bolt-in and even the parking brake cable will fit no problem. When swapping drum brakes around, you MUST have the matching backing plates for the drum width because a 1-3/4" shoe requires a different offset than a 10" x 2-1/2" shoe. If you lay one of each down on a flat surface, side by side, the offset is apparent. Without the matching backing plate, the drums will not go on.

You are in a unique situation by wanting to use a slightly wider B=body 8-3/4" in an A-body while retaining the SBP. Sounds to me like you will also want to get stock A-body axles after having the B axle narrowed to A-body width. It is not hard to find stock axles cause people are "upgrading" all the time.

For instance, I converted to BBP on my A-body 8-3/4" by basically swapping rear brake parts from a late 60's B-body and using shortened C-body axles.