1973-74 B-body vs 1973-76 A-body spindle

If you have late A body disc knuckles and you have Firm Feel upper arms then you do not need anything from Master Power Brakes. Just go to Doctor Diff and order the remaining parts that you need. You can buy the rotors at your local auto parts store or from Rock Auto. Either get 11 inch or 11.75 inch if you have 15 inch wheels. Doctor Diff has the 11.75 caliper adapters and the correct rear hung style calipers as well as the correct hoses.