10" drum brake swap for BP change

from cuda/chally forum..........." question, would a big drum setup that was on a junkyard 8 1/4 or 9 1/4 bolt onto my 8 3/4?
Yes the backing plate is the same for 7 1/4 - 9 3/4 diffs so it will bolt up the only issue would be drums from an A body with the smaller 4" bolt pattern or the 80 & newer Dodge trucks with 5" bolt pattern"