Disc question
I used the '73 disk brake setup with pin-type calipers and 11.81" rotors from a '78 Cordoba. These were the reinforced rotors like Cop Rotors. Use the longer caliper bracket with the larger rotors and all is well. The brakes are fantastic compared to the KH 4-Piston original brakes, which were good, but not great. I also did a real disk brake conversion using Liberty brakes and instructions from Mopar Action. These are also a very good conversion. One panic stop when I wasn't paying attention to lights and the car locked up all 4 wheels and stopped straight. Brand new BFG's did the rest of the work.
I highly recommend the big diameter rotors with no power booster. Feal is supreme.