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

I see nothing about where you verified timing is right. Can you elaborate? Just because the points are "good" means nothing.....except the points are good.

the timing showed just a hair or two after 0 . cold engine at idle ( not fast idle ) . timing is a little bit off from where it was , i just can't remember exactly where i set it previously . wrote it down somewhere , probably can't find that . but i can adjust the timing again . i wrote still in time , only because it was running really good . i hastily assumed that it did not jump or break . i still have not verified it with the test you mentioned yet . me mentioning the points are fine was just a follow up to two other members posts , who wanted me to check them after i accidentally went battery positive to coil negative . they did not get burned from that mishap .