My 71 Duster Twister has 10" drums and the 7.25 rear.

The local old time junkyard had (for years) a 70 Duster /6 3speed car with the 8.75 rear, but somebody took the axles and brakes a long time ago and everything was rusty as hell so nobody ever bought it.

I've been into A-bodies for 25+ years and sometimes it would surprise you to find 8.75 rears under cars that you wouldn't think would have them. I learned to look under EVERY car, cause you just never know.