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

MOPAROFFICIAL said

Condenser.

I think you said you changed points but never the condenser.

If you jump the coil from battery +.. that bypasses the ballast, rules it out and allows you to test for spark. You can do all that and jump it at the starter switch/relay on the fender by the battery with a screwdriver.

Worst case the timing chain jumped.

Click to expand...

Yes ^^^

With the cap off look at the position of the rotor, bump the starter a few times and see it the position of the rotor changed. Checking for failed timing chain.

Put a big socket on the front crank bolt, rock the crank back and forth, watch the rotor to see how much slop you have in your timing chain. if there is lots of slop there it a good chance the timing chain jumped and threw valves and ignition out of time enough so it will not run anymore.