I have a external coil, I need to know, do I splice into one of the waires with the aftermarket tach? If so, when you look at it from the top front, you have the two connecters in the back, white caseing on the left, black on the right, each with two wires. Do I splice into the back one on the white side? IF you could help me, please do, or is their somewhere I could look to find this out?