Changing from 8.25 to 8.75

8.25s were BBP, yes
The driveshaft might work; they are of similar length.
The brakeshoes and hardware and cable I think will work.

So I think a better question is what won't work?
And the answer is the drums and backing plates. And I think the brake Tee,vent is in a different spot.
FWIW
The 8.25 can take a licking on the street with street tires.