i'll take another stab at it, as i have spoken with you on this before. hopefully someone else has some input too.
the part you are asking about is called a capacitor. basically it is the same design as the condenser in the distributor, except it is for suppressing radio noise as far as i know.
are you saying it starts running again by itself when you take it out of gear while moving, or you have to shift it into neutral to turn the key to start it? you have an automatic, right?
everything i've read recently on pertronix systems says they require straight 12V. the resistor wire must be replaced with a non resistor. maybe someone else has some more input who has the pertronix system.
does it stall only while decelerating, or does it matter? the transmission can put a drag on the engine during deccel, which could further reduce the voltage, is why i ask.
i would suspect the resistance wire, if it didn't do the same thing with points in it. perhaps you are on to something with the regulator. maybe it's plum tuckered out. did you replace the ignition coil when you did the ignition swap? they dont normally cause a temporary stall, but i've seen stranger.
