I did this same swap in my 66 Valiant, (73 Duster Discs), I mounted the calipers to the rear. When mounting them to the rear, the bleeder screw is not at the top, so I had to pull the calipers and hold them so the bleeder was at the top in order to bleed them properly. I also had to use brake hoses from a Plymouth Volare/Dodge Aspen, they are longer and fit great! The 73-76 A-body hoses are too short if you mount the calipers to the rear! Good luck!!