pertronix issues

If you jumper the ballast don't do it for very long or you risk burning up the coil unless you have an aftermarket with the correct ohm rating for the full 12v.
If the Pertronics unit is running off the ballast that may very well be the problem, as those are supposed to be 12v supplied if I remember correctly.
You could still use the ballasted coil but run the Pertronics unit off the input side of the ballast.
That way the coil could be ballasted, but the Pertronics unit not.
Or you could use a coil made for the full 12v ohm rating and eliminate the ballast completely.

Check your throttle linkage for anything interfering, as I have NEVER seen any ignition system cause the stuck open feeling.