If you are talking specifically about the 73-up A body disc brake swap, then I have done this on my 64 SF. I went with the larger 11 3/4 rotors and saw no real improvement. Added the larger 76 duster/aspen calipers, and had no brakes with the 15/16 bore MC I used with the 10 3/4 rotors and 73 Duster calipers. Went to a 1 11/32 bore MC and got my pedal back. Added the EBC brakes, and feel they work great. no need for power assist. With the larger volume of the later calipers, they need to be matched with a MC that will move enough fluid to fill the caliper.
