Don't forget to check the bulkhead connector. The amp gauge wires pass through it and can cause some heat problems. Corrosion can cause erratic fluctuations in the system. You can see the heavy red wire for the charging system here.
This is a shot of my 68 New Port. It's kinda cruddy but I haven't got to the engine bay yet. This will be next as I am about to install all new brake lines and a new master and booster.