There has been some confusion on the proper way to install a Pertronix Ignitor on a vintge Mustang. The instructions that come with the unit are clear, but are also "generisized" for use with all makes of cars. There are several quite misleading statements on the instruction such as "If your ignition system presently has a ballast resistor, do not remove it". Of course this is actualy true, but what they mean is that an original 6V coil still needs the resistor. The Pertronix will not run properly when connected to a coil with a ballast resistor in the circut, it needs 12 volts. The statement that straightens this all out is "The red wire from the Ignitor must be connected to the positive side of the coil or a 12 volt switching power source". As far as a Ford is concerned, that means a 12 volt switching power source. There are many other makes of cars that use a 12 volt feed straight to the 12 volt coil, not Ford....we use a 6 volt coil with a resistor wire between the coil and the ignition switch.
Using a stock Ford 6V coil
Look at the first diagram. What this means to us is that we need a place to connect the red wire to get a full 12 volts. On an early Mustang the choices are limited. The heater positive wire and the voltage regulator both have switched 12 volt sources, but neither is sutable because of other reasons, and to be honest it's just not right. The proper way to get power is to run a new wire from the GRN/RED wire where it connects to the back of the ignition switch. This GRN/RED wire is the wire that turns into the pink resistor wire and runs to the coil + side on the original car. You must leave that wire connected so the coil will still have 6V power and just connect the new power source wire where it connects at the back of the ignition switch to get 12V power to the Pertonix. There must be a dozen "proper" ways to make this connection so I will leave that up to you, but they must BOTH be connected to the IGN terminal.
The instructions say to use 20 gauge wire.... I would use 18 gauge or better. Route it how you wish, but a clean way is to run it along the same "engine harness" that the stock coil, temp sender, oil press wires are in, you can re-tape it and it will dissapear. This runs from a gromet just behind the engine on the firewall and is a good place to run it through. (just a tip.....push it through from the engine side and then find it under the dash. Trying to go from the inside of the car is difficult if not impossible). Tie it up well under the dash because if you catch it with your toe on a quick shift on a saturday night........well, you know.
Just cut the loop connector off of the red wire from the Pertronix and connect the two with a male and female spade connector and this part is done. The black wire from the Pertronix just goes to the - (points) side of the coil. Make sure there are no condensers on this side of the coil, if so remove them.
I'm not going to go into how to mount the unit itself. The instructions are fairly clear......It's just like replacing a set of points. (P.S - remove the condenser inside of the distributor!).
Using an aftermarket 12V coil
Look at the second diagram. There are many aftermarket "hot" coils out there on the market today, most of which are made to run on 12V. The MSD, Pertronix, Accel, Mallory etc. are designed to be fed with 12V, the same as your Pertronix unit and will not run up to par when being fed with 6V through the original Ford resistor wire.
When using one of these, along with your Pertronix, the installation is almost easier as the resistor wire can go away altogether. Run the extra wire from the back of your IGN switch but you can cut the pink wire out if you like as it will not be feeding anything anyway. You can certainly choose to leave it in place if you think you may want to use it sometime in the future, it won't hurt anything.
Note in the picture that the GRN/RED wire just quits at the firewall. That's only in the picture, for illistration purposes. Make sure that terminate it properly, some folks will leave it in, some folks will cut it out. The point is connect to the GRN/RED wire at the back of the IGN switch with your new 12V power feed to the coil and Pertronix unit.
These thing are great! I have to say this is the best upgrade anybody can make to their classic Mustang or Ford. No more replacing points or condensers, or associated problems with bad dwell or timing. No slipped points or bad condensers at 3 in the morning on the way to that next Mustang show!
Just ONE more thing to note: this tech was originally written for the Pertonix 1 in 2004. Since then there are some other very good units to convert from points to electronic using your original distributor. Pertronix now has a Pertonix 2, and 3, and Crane has a really super cool one called the Crane Fireball XR-i which has an adjustible Rev Limiter and installs like the Pertronix units. All of these are going to need a 12V switched power source so you can install them the same as the diagrams and instructions show above. Read any individual units instuctions to identify what wiring colors they may use.
Happy cruizin'......, Hal.