Bulkhead wire 64 Barracuda

I can't say about the 64. The 65 has 2 solid buss bars, one of which connects to the output terminal on the alternator and the other to the big lug on the starter relay. On the inside the wire that connects to the battery (via the starter relay) goes directly to the amp gauge. The other wire on the amp gauge routes back to the wire from the alternator. This wire has a splice with wires going to the ignition switch and headlight switch. Again, this is on the 65; the 64 might be different.