On my 68, I replaced the red wire from the starter relay to the ammeter with a new thicker solid wire going through the bulkhead connector with properly sized fusible link, and didn't use the connector. Then I tied the two wires together that would've connected at the ammeter. I also ran a new thick charging wire with properly sized fusible link from the alternator to the starter relay. The system works great for what I need.
I also replaced the ammeter with a simple volt gauge in the cluster.
