Question about ignition coil

[billfrank85]

Hi, on these ignition coils there are two other electrical plugs aside from the "coil wire" -- what do they do? I thought I read somewhere that one of them was for the tach signal or something but I wanted to know for sure. Thanks.

[5 Speed Speeder]

the blue one is the tach signal. that's all i know. i had a distributor that had the jumpy tach and rocks sound/misfire and i checked out the wires and the insulation around the blue wire was broken. got a new distributor from the junkyard and all is well.

[noidea24]

Stock coil: you have two plugs, both with 2 wires. On each plug you have a positive and a negative. On #1 plug you have a blue wire that is used for your tach, and a black and yellow that goes to the radio condenser then to the distributor.
On plug #2 the blue wire is the primary ground for the coil, and the black and yellow is switched ignition.

[noidea24]

You can wire a universal coil (super stock, msd) if you wanted.
On a universal coil you have a positive terminal, a negative terminal, and the coil wire. You can cut the two plugs off your stock coil plugs, and connect both black and yellows to the positive and the blues to the negative.