Yeah but the parking brake cable area attaches differently.
You MUST match the backing plates to the brake width. I think there are 3 different offsets? For instance if you want 10" X 2-1/2" rear brakes, you need the backing plates for that combo. My personal opinion is 11" drums add a LOT of weight and not necessary on an A-body. It'll actuallly slow your car down with all that additional rotational mass.
Relying on my memory here....I believe late in the A-body run, the brakes went to 10 X 2-1/2" so that's a good source. (Look at 4 doors)These were on the 8-1/4 rear but they fit the 8-3/4". 7-1/4 bolt pattern is different.
My own personal experience; I used late 60's B-body backing plates, shortened and resplined C-body axles and went with 10 X 2-1/2 brakes. Bought hardware, shoes and new drums. The parking brake cable was a direct fit. This adds 3/8" to the track on each side.