Have you bypassed charge current through the bulkhead connector yet? That is the weakest link in the system.

Ammeter connections are a weak link but not as much as the bulkhead connector.

True story... on a '74 D200 the bulkhead connector lasted until about year 5. Then melted. Emergency bypass lasted until year 20 when the truck was retired due to frame rust. The ammeter connections lasted the life of the truck.

If the alternator and electrical loads are stock, the ammeter should be OK with thoroughly cleaned and tightened and greased connections. If you have increased loads or alternator output or both, best to bypass the ammeter also IMO.

A nice heavy wire from alternator output to the fender relay bypasses both. Fusible link 2 gauge sizes smaller than the bypass wire recommended. A voltmeter is needed with this bypass as the ammeter will not be functional.