1972 dart - stopped running while at 50 mph ? no warning

This really is just dumbfounding, this should be a 10 minute diagnostic job with a hot wire from the battery. We even have a video posted on how to do it.

We knew how to do all of this points stuff when we were 16 years old, 50 years ago. Motorcycles, cars, trucks, tractors, lawn mowers you name it.

Keep digging into it, that is how you learn. If you don't know, you don't know.