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

yes , running really good . replacing the rotor got it running . the rotor had punch through , i just found out from 67dart273 what that is and what to look for . i didn't see it until really closely examining exactly where to look . i still have to fine tune the timing . and trying to figure out what caused the punch through . but , at least its running and driving .