if the A-body 8 3/4 has the stock axles and 10 x 1 3/4(skinny) brakes

they do not mix with any of the larger brakes

what axle offset do you want to run? what car ?

if you want the large brake with correct axles offset..any 10x2-10x2.5-11x2-11x2.5 brakes set up from any 8 1/4 - 9 1/4 - 8 3/4 will work

maybe some of the spring hardware can be used,but its cheap to buy new hardware kits and a good idea most times IMHO