Voltage regulator problem with 1968 Dart

How does power get to the main splice? The reproduction harness heavy black wire?
Not sure which wire your talking about, the one that would normally go to the BAT stud on the alternator?
H'm. This is important so lets look at the stock wiring for minute.
The car has two power sources, alternator and battery. The factory wired them together at the main splice. The main splice is where all of the other circuits are tied in except the starter motor. Whether the alternator is providing power or the battery is providing power, power goes to the main splice and then wherever needed.
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So if the alternator output is cut and taped, and the battery feed/charge connects to the alternator, this is what I'm picturing.
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That can't be right. It's connected somewhere.