Thanks a bunch Kern Dog! My car came with front disc / rear hubs and I really wasn't planning on converting the rear to disc if I didn't need to. This helps a lot and is greatly appreciated!Here is one that is guaranteed to be a winner.
12" front discs from a late 70s B body, 2.75" single piston slider calipers from a 1976-89 F-M-J-R body and 10" rear drums with quality shoes.
15/16" master cylinder whether you use a power booster or go manual.
I have this exact system on my Jigsaw Charger. It stops quite well and has great pedal feel.
4 wheel discs will stop better but may not be necessary unless you plan to road race the car.
As @Kern Dog said above. I personally like the "feel" of manual brakes. You can get a cast iron 15/16" one for a '74-'75 A body. Also leaves more room and less clutter in engine bay. From Cass/Dr Diff on the master cylinder. View attachment 1381961