Disc brakes

These are the parts. Dr. Diff has adapter for ball joint, vs larger ball joint control arms.

Mopar Large Bolt Disc Brake Conversion (A- Body) | eBay

I was able to get donor parts off this site, FABO, with the peg leg 7 1/4. Rebuilt following Bruce's sticky, (great thread). Rebuilt Parts still available. PartsGeek, NAPA, ... Not really saving in the long run , but fun. Painting old. Installing new. Collecting parts. Can be upgraded to larger diameter 11" rotors with newer/ longer caliber adapters, (with 15" wheels), 5th Ave etc., Volare.

AR Engineering made an adapter specific to the 1973 - 1976 a body DRUM spindle I don't think it is still availible. It would adapt Viper brakes.

Mopar musclecar brake upgrade | AR Engineering

Scarebird another route.