Have had 40+ Mopars more than 30 with ballast resistors. People said they blew. Never blew a one.
Never understood why GMs needed that dwell angle adjustment on their point ignition cars. Just added unneeded baggage. Worked on some pretty sophisticated motors back in the day.....blew the doors off of Chebbys all day long.
I think it was a moistureproofing issue. They didn’t handle things well when things got wet. At least that was my experience. Something somewhere would short/surge and poof. The resistor turned into a fuze.