Really weird ignition issue...

i think.....but am not sure that the phasing is set up so that everything comes into best alignment between mid advance and total advance

low rpm, long dwell, biggest spark energy, can jump a longer distance from rotor tip to cap contact with less impact at the plug. jumps to closest rather than close cap contact

at hi rpm under load, dwell is limited by rpm, has impact on spark energy, closer alignment needed between rotor and cap contact to avoid mis fire and maximise spark at plug without wasting too much jumping a slightly bigger distance.

and i say i think because it impacts which end of travel you adjust when recurving a dissy.
do you take advance away from the advance range, by advancing the return position to decrease total advance or do you limit it at the total advance end...can't remember, i knew this cos i did it, but if could remember id be more confident in what i say above
i do know doing it the wrong way can leave the long loop spring doing nothing...
so its probably the starting point that is altered rather then the end.

Based on my own limited distributor fiddling i don't think they are set up with the "best" positioning for reluctor and rotor at stationary or for low rpm.

or my distributor was a "wrongun"

turning the reluctor over does impact phasing. a reluctor peak to the right of the pin will be to the left of it with the reluctor tuned upside down from its current position. the tiny pin position on the shaft is hard coded to the rotor position on the shaft but the reluctor can go onto that pin either way....... or it can on mine.... i'll have to qualify it with that, cos mine is a bosch made chrysler style distributor. not a chrysler/mopar distributor, yours may differ.

Dave