Converting to HEI, need 12v (Ign 12) source

RedFish said
Something that most don't realize... While the switch is in the run position current is present through the ballast resistor, on the blue wire , all the way back to the ign' switch. So even where a ballast resistor isn't required, it and a diode and a relay would put power at the right places at the right instances.

This is "sort of true" but the fact is there is not enough drain on there to bother

RedFish said
Contrary to popular belief in this forum, the OEM engineers were not idiots.

That might or might not be. There's been plenty of idiotic decisions made by automotive engineers and designers over the years, in general. But even if they weren't idiots the 'low buck' design of these electrical systems was borderline. All you need to do to prove that is to do one or two things.........add some accessory such as a two-way radio that would have been "back in the day" and or put a larger alternator on the car.

I've seen plenty of electrical problems in these girls "back then" and I didn't need Al Gore or the internet, either.

ONE of them was my own 70 V code RR in the early seventies