Are you talking about the wire that goes to the side of the ignitor housing (thats the name of the unit that houses both the distributor and coil) and attaches there with a screw on cap...it attaches to where the #2 is in the image below?
If so, it comes from the on/off switch on the dash and runs to that location. On the on/off switch, there are 4 wires...2 rows of 2. 2 of the wires on one side are both number 11 wires. On the other side is a wire numbered 12 on the top connection and a wire numbered 27 on the bottom. The #12 wire is the one that feeds power to that screw on plug at the ignitor housing.
If that isnt clear OR I assumed the wrong wire, please post so I can help you better.
By the way....WELCOME!!!!
Lord send your Holy Ghost into our hearts and make the desire of our hearts Your Will.
Pro-choice, that's a LIE, babies don't choose to die!!