Here's another version of the piggy back terminal.
View attachment 1715583273
Either one allows the original wire and connector to remain intact.
A little confusion can come from the diagram saying wire
to ignition. Most people think of power as coming from positive. So rewrite that in your head as wire
from ignition. What that really means is ignition switch's 'run' wire. Its generally dark blue or dark blue with stripe.
Ballast resistor or not. The ballast resistor is there to control the amount of current flowing through the coil.
IF this particular Pertronix system has a current controller for the coil built in, then the ballast is not needed. If it doesn't have a controller in it, then the ballast is needed.
