I did a disc brake swap on my 71 Swinger. The car originally had 9 inch drums all the way around. The donor car was a 74 Dart Sport with big bolt pattern manual disc brakes. The problem after the swap is I have to push really really hard on the brake pedal to get my Swinger to stop. This is a list of used parts I installed from the Dart Sport...spindles, proportioning valve, upper control arms and the brake pedal push rod. This is a list of new brake parts I installed when I did the swap...rotors, calipers, pads, all rubber lines, all steel lines and master cylinder. When I ordered the master cylinder I ordered one for a Dart Sport with manual disc brakes. The rear in the car was also swapped from the 7 1/4 to an 8 3/4 with big bolt pattern axles from Doctor Diff. All the brake parts on the rear are also new...drums, shoes, wheel cylinders and hardware kit. The shoes in the rear are adjusted up until they just start to drag slightly. I have bled the system several times and have plenty of fluid coming out at all four wheels. I'm not sure what else to check. There really isn't much difference between the drums that where on my Swinger and the manual disc's I have on it now.