in that case I'd keep it simple and get a 70's square back dual pulley alt & put it in & you're (pretty much) golden). I would suggest cleaning ALL terminals/connections expecially the bulkhead & doing Nachos' bulkhead parallel bypass is a good move which is simply to run the (2) main in/out circuits, the feed in from the battery past the fusible link into/thru/past the bulkhead and the feed out from the bulkhead (same deal) to the alt: solder in 2 pieces of wire for a direct connection as opposed to the 2 pairs of male/female brass terminals that connect those 2 circuits now. you are replacing those (2) high current connections from brass pull apart terminals which are subject to corrosion to a direct wire on both of em. EDIT #1 clean all terminals #2 strive to keep the ammeter needle as close to 12 o'clock as possible which tells you the system is in equilibrium (neither charging or discharging) and that the alt is supplying only the current the accessories are on are demanding nor is the battery being charged or discharged. #1 culprit is using the alt to charge a dead or partly depleted battery. Use a battery charger on slo charge