An Electrical Nightmare

Since you have to start over again somewhat, I would start with simplifying the wiring and do some mods you want to have done anyway in time;

- Install a HEI module instead of the Mopar ECU. This deletes the ballast resistor right away and everything runs on full 12-14v battery voltage.
Best to switch all this with a relay too.

- Next install a relay in the headlight wiring to take the electrical load of the headlight-switch.
Another possible fire-source eliminated.

- 3rd; bypass the AM-meter completely and run a new thick gauge wire through a dedicated firewall connector. Install a Volt-meter.
This relieves the bulkhead connector of another high current wire.