Mustang Pertronix Ignitor III Ignition (1965-1974) Installation Instructions

Tools Required:
  • Ratchet & Socket Set
  • Wrenches
  • Screw Drivers
  • Wire Strippers
  • Wire Crimping Tool
  • #10 Insulated Ring Terminal
  • Timing Light
  • Spark Plug Wrench
  • Feeler Gauge/Spark Plug Gap Tool
  • Optional:
  • Heat Shrink Tubing
  • Heat Gun or Lighter
  • Pertronix Ignition Power Relay
  • Remote Starter Switch
  • Volt Meter
  • Drain Coolant
Install Difficulty:
  • Difficulty
  • Easy Project
1. To start the installation of the Mustang Pertronix 71281 Ignitor III Electronic Ignition, or any work on my distributor, my habit is to check the timing and set it at number 1, top dead center. Make sure you are in neutral or park and that the parking brake is applied. Use the remote starter switch connect between the positive battery terminal and the post marked S on the left side to the starter solenoid to bump the motor over until the rotor points to #1 tower, the points open up and/or timing mark on the balancer lines up. If the engine runs pretty well, then this step isn’t necessary. If you are going to reuse your cap and wires, please mark them for easy replacement as follows.
2. I removed cap, rotor, plug wires and heater hoses for ease of installation and clarity. The installation can be done with these parts in place by just pushing them up and out of the way.
3. Disconnect and remove the old coil. A 9/16” bolt secures the coil bracket to the engine block. Removing the heater hose makes this easier to get to.
4. Carefully pop lose the clip securing the vacuum advance arm with a flat screw driver. Wet the end of your finger, dab the clip and lift it out. Remove the vacuum advance module by taking out the two screws with a standard screw driver.
Mustang Pertronix Ignitor III Ignition Install Image
5. Remove the two screws securing the points breaker plate with a Phillips screw driver, push in the wire grommet and lift out the entire assembly.
Mustang Pertronix Ignitor III Ignition Install Image
6. Clean and inspect the mechanical advance weights and springs. Replace if necessary.
7. The Petronix Ignitor III assembly can go in only one way. It uses two screws: the pan head screw attaches the ground strap and cannot go into the countersunk hole. There’s a countersunk screw for that.
Mustang Pertronix Ignitor III Ignition Install Image
8. Gently pull the wires and grommet through the base of the Mustang distributor, secure the ground strap and carefully clip the vacuum advance arm in place. You can test the vacuum advance module by attaching a hand held vacuum pump, which should hold steady at 18-25 Hg, or you can also just suck on it and the arm should move accordingly. Replace if necessary.
9. Secure the vacuum advance module with the two screws and check that none of the wires hit the distributor base or bind up.
Mustang Pertronix Ignitor III Ignition Install Image
10. The FlameThrower III coil is slightly smaller than the stock Mustang ignition coil. If you tighten the small retaining bolt holding the FlameThrower coil in place you won’t be able to thread the 9/16” bolt in. Here’s where the 1/4” and 11/32” wrenches come into play.
11. Snug everything up to the point where the Petronix 44011 Flamethrower coil just barely fits, and to where you can still get the 9/16” bolt in. Install the coil bracket on the engine block and hand tighten without the FlameThrower coil to where you can get to the 1/4” retaining bolt and 11/32” nut with your wrenches. You can also cut a strip of bicycle tubing to wrap around the new coil to make it fit as well.
Mustang Pertronix Ignitor III Ignition Install Image
12. Slip the FlameThrower coil into the bracket and tighten up the retaining bolt with your small wrenches, holding the coil firmly in place. Then tighten the 9/16” bolt to the engine block. The heater hoses can now be reinstalled. Do not forget to top off your coolant level.
13. The red and black Ignitor III wire can be camouflaged inside heat shrink tubing. Give yourself enough wire to allow the distributor plenty of movement to adjust timing. Trim the extra wire.
14. Strip the wires back 1/4" and crimp the two ring terminal connectors that came with the Ignitor III kit. You need one more ring terminal for the ignition wire; unfortunately, the FlameThrower posts are not long enough to accommodate the stock ignition wire’s push-on connector. You need a 3/8” wrench for the nuts on the FlameThrower coil.
Mustang Pertronix Ignitor III Ignition Install Image
15. The Ignitor’s black wire connects to the negative (–) side of the coil, formally the distributor side of the old yellow top coil. The red wire and the car’s ignition wire connects to the positive (+) side of the coil, formally the battery side of the old coil.
16. The gap from the stock Mustang spark plugs of 0.035” works fine for street use. Pertronix says you can increase the gap up to 0.045”, but I wouldn’t do so unless you have a full 12 volts coming to the coil. See below for additional instructions regarding that. Re-install the cap, rotor and spark plug wires. Check the engine timing and set as required.
17. ADDITIONAL INSTRUCTIONS: The Pink Wire, built-in resistor: All Fords of this era have them; but it is not located in a convenient, easily accessible location. It is buried up underneath the dash.
18. With an 18 gauge wire, ground the negative side of your coil to the car or battery. With your volt meter, check the voltage at the positive terminal on the coil. If it reads around 12 volts, you are good to go. If it reads around 9 volts, there’s a resistor in the system. Don’t leave the key on for too long.
19. With the low resistance FlameThrower III coil of 0.32 ohms, there should be no problems with a low voltage situation; however, for best performance and high RPM use, I definitely recommend bypassing the pink wire by replacing it with 12 gauge wire or using the Pertronix 2001 Ignition Power Relay. Any 30 amp relay switch will do.
20. With a full 12 volts to the coil, feel free to open up the spark plug gaps to 0.045” and raise the rev limit up to your desired RPM. The default setting is 5000 RPM; it can be set as high as 9000. Pertronix has a video on their web site showing you how to program the built-in rev limiter in your new Ignitor III Electronic Ignition. It is at:
21. The Mustang Pertronix Ignitor will work with any coil with 0.32 ohms resistance or greater. Other coils typically have a resistance of 1.5 to 3.0 ohms. If you use another coil, there will be a risk of a low voltage situation and the Ignitor III will shut down after a short period of time. Here’s why: If all you have is 9 volts with the FlameThrower III coil, you can safely run a stock engine and most street engines as well - 9 volts divided by 0.32 ohm = 28.125 amps, which can run most anything out on the street. If you use a different coil, 9 volts / 1.5 ohms = 6 amps to run the ignition and may result in a low voltage situation. For best results, lose the Pink wire. 12 / 0.32 = 37.5 amps!