Overcharging Issue & Car Start Issue

+1 on bad connection(s). The voltage regulator senses the 12V at the switched ignition supply. If the voltage dips, the regulator boosts the field so the alternator voltage increases. So if the ignition circuit is a volt low, the battery voltage is a volt high.

Check the bulkhead, ignition switch, and ammeter wiring. Re-seating is not doing it. Time to clean, tighten or change connector terminals. Packard 56 style terminals.