Re your charging issue. Does a 72 have the electronic regulator with the so called dual field alternator?

If so your problem may be under the dash. My dad had a 75 Gran Fury that randomly refused to charge and he blamed it on "that new fangled" electronic regulator. He changed it back to a mechanical regulator with a single field wire alternator and it never missed a lick.

Years later he was under the dash changing dash lights or something and noticed the ammeter connections were green as grass. Cleaned them up and all of a sudden the ammeter actually showed activity. Put the original alternator and regulator back on and it worked until he sold the car.

Apparently whatever tells the electronic regulator that the battery is full is sensed off the ammeter circuit and it was reading the resistance from the bad connection as a fully charged battery and not turning the ground on to the field.

Kevin