Wiring modifications for High Energy Ignition (HEI) - 1963 Chevy II Nova

After adding a Pertronix unit (Ignitor II, Flame thrower II coil & plug wires - install info here) to my car, I needed to get a full 12 volts to the coil/distributor. It is possible for HEI and/or the Pertronix unit to run on less than 12 volts, but it is not recommended. As far as wiring goes, there were three things I needed to do:

1. Remove the pink coil/distributor wire completely. It goes from the R terminal on the starter solenoid and to the coil. It's purpose is to provide 12 volts to the coil during startup.
2. Remove the white, cloth covered wire that runs from the starter to the firewall. This is the resistor wire. It drops the voltage from 12 volts so that the points in a points ignition system don't get burned up. On my harness, the resistor wire was coupled with the distributor wire at the R terminal on the starter solenoid. It is cloth covered at the end that connects to the starter solenoid, but when it gets close to the firewall plug, it is connected to a 'normal' white wire that is not covered with cloth. After the initial startup, it provides 'reduced' power to coil/distributor through it's connection with the coil/distributor wire at the starter solenoid.
3. Add a 10 gauge wire to server as the + coil wire, running it from the firewall plug to the coil/distributor.
   

[WARNING/DISCLAIMER: This page documents my upgrade/conversion and does not replace the manufacturer's instructions in any way. If you choose to use this information, it is at your own risk. I take no responsibilty for the results. Modifying your automobile in any fashion can have dangerous and/or deadly consequences. You should always have a certified mechanic check your work.]

To remove the engine wiring harness (the one closest to the engine), I carefully squeezed the black tabs and gently pulled the plug out by the housing (not the wires). Once removed, I laid it out on a clean surface and unwrapped it to figure out what I was dealig with. Here are some pictures:

The coil (pink) and resistor (white) wire pictured need to be removed. I untaped them from the harness and removed the resistor wire from the firewall plug. To remove the resistor wire from the firewall plug, I used a needle to depress the tab holding the connector in place. Once this tab was depressed, the wire slid out easily.

After removing the resistor wire from the harness, I removed the connector from it, then soldered the connector to a new 10 gauge wire. This wire will run from the firewall plug to the coil/distributor. After bending the tab on the connector back to its original position, I pushed the wire and connector into the firewall plug housing until I heard a faint click.

After taping the new wire to the harness in a couple of spots, I reinstalled the harness in the car for some testing. Reconnecting everything other than the purple starter wire, I checked the (new) coil wire with a voltmeter. With some assistance from a friend, I checked the coil wire to make sure it had power when the key was in both the start and run positions. After confirming this, I removed the wiring harness again. I checked all of the connectors for corrosion and did some light cleaning. After adding some additional wiring for gauges and other accessories, I rewrapped the harness and added some dielectric grease to the firewall plug before reinstalling the entire thing back into the car. The new coil wire was connected to the + terminal on the coil. The only wire connected to the starter solenoid now (other than the positive cable coming from the battery) is the purple wire connected to the S terminal (terminal closest to the block).

As stated earlier, this was done after installing a Pertronix unit in my car. I believe the process is similar for any standard GM HEI setup. If you have any questions, feel free to contact me by clicking here. To check out my installation of the Pertronix unit, click here. Once again, if you attempt to make these changes on your vehicle, refer to your owner's manual and have a certified mechanic check your work.