You may not know about the fix yet, but you probably still have the factory wiring problem of the output from the alternator being routed through the firewall then the amp guage and back out through the firewall to charge the batttery.

I'd look into resolving that next.

1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)