Slant 6 no fire...

Unfortunately, although these Mopar ignition systems have been around for 42 years now, people still can't understand how to diagnose them.

The number one thing that kills spark to a Mopar electronic ignition is ECU failure. If you drive one of these cars, carry a spare, always. I had one fail sitting at an intersection. One second the engine was running, the next it wasn't and didn't again until the box was replaced.

The second most common is the ballast resistor. Those almost always fail the same way: the engine starts and runs as long as the key is held to START. Let off and it quits. Again, carry a spare.

I'm sure coils and hall-effect switches inside the distributor do fail, but that's way down the list. Where did a voltage regulator come in as causing a car not to START? That's the charging system, nothing to do with ignition unless you are an amateur parts replacer.