72 Duster Rear End and Brakes

I have recently rebuilt my 318 duster and on the dyno I am creating 423hp(at the crank) and I am curious where everyone has bought their 8 3/4 rear ends??. Also I was wondering if anyone has done a disc brake converstion with their 8 3/4 rear ends. Im looking for info on a 4 wheel disc conversion kit. Thanks in advance!!! :notworth: