On those style you should not need to fuss with the ground terminal. They should be well grounded through the brackets.
I would NOT go bigger than 60A if you have stock ammeter / bulkhead connector. This is not a hard and fast rule, but consider the "factory."
Even Ma knew the bulkhead / ammeter was a problem "back then." There exists on heavy optional (60-65A) alternators, and I'm talking about "as they were" optional new................what is known as "fleet....taxi wiring". This envolved running additional HEAVIER wire through separate grommets in the bulkhead and to the ammeter. The original bulkhead red wire was essentially abandoned.
Here's the situation you get into on very heavy alternators.................
You have a "normal" car, but you've installed a modern 80A alternator, and, parked somewhere, you left the lights on, parking lights, ran the stereo, whatever, and now the battery is LOW. But you start the car, you leave the event, you are driving home.........in the dark. Maybe you have a car with AC (just sayin). You certainly have the headlights. Maybe, back in the day, you have the heater on. You are playing the "big" stereo, etc. AND ALL THIS TIME the alternator is trying to "catch up" the low battery. The alternator will really be cranking out the amperage. The ammeter is buried to the right.
The result is, this big 80A alternator is "heating up" the bulkhead connectors--------which might already be damaged earlier, --------and the ammeter.
This is why..............this:
http://www.madelectrical.com/electricaltech/amp-gauges.shtml
