Hi, I just got the HI-6s ignition and when I hook it up my Tach bounces around.

The first time I hooked it up the car ran great.
Than I extened the wires on the GM harness and the tach started bouncing.
I extended the wires with same gauge wire, heatshrink and electrical tape over that.

I called the crane tech line and they told me that its interference and to get a .5watt resistor and wire it in with the tach lead wire.

My question is, is there a way I can wire the ignition so there is no interference.
Which wire is the tach lead wire???