Factory ammeter

If you're going to bypass the ammeter, just put both connectors on the same post, assuming it has the insulator in good shape. You can bolt the wires together, tape them good, and wrap them in insulation such as a rubber hose if you would rather. I'd have the alternator checked for it's output and get a regulator to match. I wouldn't use anything higher than about 60-65 amps with a stock '69 harness. If you have any high amperage draws, such as a high powered sound system, run a separate fused circuit for that straight to the battery.