1) Is the tach wire the smaller-gage, white wire on the coil?
2) Does the wire go to the instrument cluster tach only or is it involved in any other electrical function?

Background - My tach is bouncing around above 3K rpms. When the car is floored, the tach goes to zero always. I have a monster tach ready to go in, so I'd like to simply disconnect the factory tach wire at the coil since it may be shorting somewhere. Then I would just run a new wire from the coil through the firewall and into the cab.

3) Any problems with doing this?

 

use the small white wire that is off the coil that is coming out of the harness, if you look, 2 wires(in 1 plug) off the coil go to the dist., and 2 go in to the harness, use the one that goes in top the harness, all it goes to is the tach, the ECM gets the RPM from a different source

 

That's what I was wondering. Thanks!!:hail: