The Pertronix remark/rebuke is gratuitous at this point. This problem is elsewhere.
However, this thread was taken there: I have had no problem with Pertronix (so far, on 6v or 12v on 235 and 261 high-pressure engines), after I make sure that the distributor does not have an intermittent ground - I ran a ground-wire from a distributor-cap clamp-screw to one of the bolts that holds the coil-clamp to the head.
Nonetheless, since so many people seem to have problems with a Pertronix unit. I keep a spare distributor in my truck, with a set of properly adjusted points. Like many insurance policies, it has never been used. Guess I have just been lucky.
Oh yeah, I almost forgot, I have had more problems with bad new points/condensers than I have had with Pertronix units. Nonetheless, I do not recommend an electronic ignition of any sort on a non-racing 216/235/261, unless you simply want to try something unconventional (that will most likely no measurable increase in performance or reliability). I carry a spare set-up distributor, either way.
Last edited by tclederman; 08/12/2017 11:51 PM.