I need some help. I have a 1990 IROC-Z with the 5.7 350. The person that owned the car before me had installed a aftermarket tach and now I am wanting to do the same. I believe there is some wiring left over from when he had installed it and I have included a picture. Could anyone tell me what wire goes where or what I need to do to get it hooked up? Thanks!

 

red: 12v
black: ground
green: tach terminal on dist, or ignition box
white: i belive would be illumintion.

best bet, fid out what kind of tach you have, then do a google search for it and see if you can find instructions on how to hook it up