I have a 1972 Camaro with a factory tach. I am completing a restoration and have changed the fuel/ignition to the Holley Sniper 1 EFI with the complete plug and play ignition box, coil, and distributor. The challenge I am having is where to hook the brown Holley tach wire to the original harness so that the factory tach works. Has anybody run across this? I thought it might be either the coil positive or coil negative wire. Any other thoughts on this application?

 

Negative side of the coil. Positive side may pick up a signal through the coil be all tack I have even seen pick up the signal from the distributer side of the coil. Distributor grounds the coil. Positive side is just Constance power.

 

Thank you for that response. The reason I asked was because I was trying to start the car one day and could not get it to start, but once I disconnected that wire, it started. So my assumption was that connection ws wrong. It apparently was just a coincidence because tonight I finally got some time to work on it, and the negative coil wire worked, tach is working! Thank you for the help!