I believe you run the 2 Pertronix wires to the respective coil primary (+) and (-) terminals and you use the ballast with your OE coil and dont use the ballast if going with a Pertronix coil either a (I) (II) or (III) Pertronix coil to match the respective (I) (II) (III) Pertronix kit that you have. Wired that way if using a ballast the voltage to the Pertronix would be reduced & not sure if that is a problem or not & if so it instead requires the P hot wire be run to switched 12V to bypass a ballast if a ballast is used. What are the ohms of your current coil/ballast and what is the ohms of the P ballast. I would call P & give them your coil ohms & see if they want you to use their ballast. EDIT found my ignitor I kit for a toyouta that I bought at a swap meet for $2. I see that with a ballast that you do run full 12V to the P