Slant 6 wont idle after warm

Great result. A few details would make this thread more useful to others. We now guess a slant-six engine, before ~1971 (points). Most likely, it needed new points or timing/dwell adjusted (i.e. routine "tune-up" back in the day). But, e-ignition is smarter. What system did you convert to - Mopar, Pertronix, GM HEI module?