Rally-Pac wiring

Woody3882

5 Year Member
Jun 19, 2018
84
9
18
Bradenton Fl 34212
65 Mustang coupe 289. I need some hep with a simple task that has turned into a total cluster.
I am trying to install a "Mustang Rally Pac" clock and tachometer on my 65.
No problem with the clock, but the tachometer install sheet states that there must be a ballast resistor or a resistor wire for the tac to work properly. The 65 only produced the resistor wire from the ignition wire to the coil. But in order to accommodate the pointless distributor with the full 12 volts, the resistance wire has been removed and replaced with non-resistance regular wire. This practice was commonly done years ago to get the full 12 volts and better performance with the pointless distributor.
My question is this, how do I get the tachometer to work without a resistance wire or can I modify somehow to make it work.
Question #2 The tac has three wires, one for the light bulb (black with blue trace) no problem. The other two wires are the issue, they are one red and one black. I have repeatedly read the instructions and viewed various videos that give conflicting installation instructions. One wire goes to the ignition source and the other goes to the coil. Does any one know which wire goes where.
I appreciate any input that anyone can give
Thanks I appreciate it
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I know this post is a few years old but,
Did you ever figure out what your problem was with your rally pac?
To CSXENG
The question drew very little interest in the Mustang community and I still have the rally-pac with no working Tachometer. I just hope that any one that is researching the issue with the non-functioning rally pac tachometer learns is that there are two types (voltages) for the tach. 9 volt (to the distributor) if your Mustang is original and 12 volt (to the distributor) if it has been upgraded. The easiest way way to tell is that if you have a petronix electronic distributor then odds are that it has been changed to 12 volts. Also as of this date I have not been able to find anyone that sells replacement 12 volt rally pac tachometers or that converts them from 6 to 12 volt
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I was doing some searching around regarding this question and the answers are all over the place. Are there no instructions that come with the 12-volt distributor to make it play nice with the factory tach?

It's times like this I wish I remembered more from the electronic principles course I took fifteen years ago. A wiring diagram would be super helpful.