Flickering Lights

You might be confusing him. He has a 70/ later regulator

Try not to overthink this. I told you earlier. Regardless of car model there is ONE source of power, ONE wire coming into the engine bay that is "hot in run" from the key switch. ONE

EVERYTHING under that hood that gets powered with the key "in run" comes off that one wire
(On a side note you might want to put a relay in that circuit specially since you are "in to" it)

The run wire--depending on year--feeds the ignition system (ballast), the VR IGN terminal, electric choke if used, on later models sometimes some smog doo dads. ON A 70 OR LATER with the electronic VR it also feeds power to one of the two alternator fields.

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On a second note, now that I've said (again) that there is one source of "run" power, it is also important to realize that the RUN voltage goes DEAD, that's right DEAD in "start." So how does it fire? There's a bypass circuit, IGN2, a separate contact on the ignition switch that works just like the start contact--only separate. IT goes from the key through the bulkhead to the coil+ side of the coil--and provides spark power when the car is cranking.