if it has the same wheel bolt pattern, and has drum brakes, it should work- but maybe the BOP axles used a different axle tube end, so look out for it. they are the rears that have the center cover that isn't round, but has a big chunk taken out of each side. you'll know it when you see it.
also, look out for the 76 or so and newer Monte Carlos and Grand prix's with the huge (11"?) rear drums- those backing plates would have to be a couple inches bigger. also, 78 and newer A and G bodies have a funky backing plate that only uses like 2 1/4" bolts to hold the backing plate to the axle- i can't see how those bolts don't break.
other than those few exceptions, any GM midsize car from the mid 60's to the late 80's are close to the same- if not THE same.
you don't plan sincerity.
you have to make it up on the spot.
wanna hear about 20 years ago when i was too smart to know any better?