I am putting a 6.0 LS engine in my 73. I have just the tach from a 75-78 (electric) No connetors or wires. Look at the back of the tach there are three push on lugs. One to the left side, one to the right and the last one is below the one to the left. I need to know which one is Possitve which one is Negative, and of course the last one will the tach signal wire. Please Help!!!

 

Hey cuda, I checked my '78 wiring diagram but it is not a pictorial, it is not giving me terminal locations on the tach. I'll check one other possible route.

 

Cuda, I tried to find the old control board that I took off of my tach, couldn't locate it. I don't think your tach is going to work without the circuit board on the back of the tach, you could order a new one through any of the Vette supply outlets and I think the terminals are marked on the board.

 

I have the curcuit board, that is what has the three lugs I discribed and there is no markings on the orginal. I do appreciate your effort. I do find it hard to believe that this information is this hard to come by.

 

Hey Cuda, Im having the same problem with the tach wiring as you did back in may of 2010. I was wondering if you ever got the answer you were looking for and if so could you share the answer to that mystery with me?