Overcharging

Don't overthink this:

1...You can NOT MEASURE low resistances with a meter. You must measure them with current flowing to create a voltage drop, in other words, "operational."

2....The simple deal is, the VR power (and ground!!) MUST be same as battery. MUST

3....There are only so many places for voltage drop in that circuit, just follow the path. (Might by a bit different for the 74/75, but essentially same)

The "functional path" is from battery, ..........to starter relay stud.......through fuse link.........through bulkhead connector.........to ammeter (big RED).........through ammeter........out on big BLACK.........to underdash WELDED SPLICE..........and branch off from the splice............to IGNITION SWITCH CONNECTOR..........through the SWITCH..........back out the SWITCH CONNECTOR (on ignition run line)...........back out BULKHEAD CONNECTOR.......and out into engine bay, l branch off to ignition, and to VR

EVERY POINT itemized above is a place for some drop. The major offenders are the bulkhead connector terminals, and the ignition switch

One again, adding a relay is likely the easy way to eliminate this

4...Don't forget the ground.........I like (on a v8) to use the unused holes in the rear of the driver side head. You can install a short starter cable (eyelet to eyelet) a foot or foot and half long, and bolt the other end to the master cylinder stud, or a good bolt through the firewall

Remove and scrape around the boltholes on the vr, and the firewall. Remount with star lock washers. Some guys use no10 ground jumpers between the ECU and VR and a good ground point such as the block. The block is actually the central main ground as that is where the battery is grounded. The body is often "poorly grounded" to the battery