As I understood it, and I could be wrong on this, but the purpose of the ballast resistor is to reduce the voltage going to the mechanical points on earlier cars to reduce the likely hood of frying/burning them, and nothing else. I believe it reduces or basically halfs the voltage going to the points.

i took apart the spare tach and there are 3 wires. Are those the modifications i would have to make? By connecting the negative and positive to the orignal mount as well as the singal wire? because the actual tach is the same just a different harness is it not?

The brackett coming off the back is from the 73 and later I believe. My 72 just has the 2 screws and it doesn't work. Thinking about geting something aftermarket. Any suggestions?

i have a 73 and mine just has the two wing nuts on the back holding it in place, but i would like to know if the wiring modifications i have to make are just the negative postive and signal wires

i have a 73 and mine just has the two wing nuts on the back holding it in place, but i would like to know if the wiring modifications i have to make are just the negative postive and signal wires

I am not sure, as I have never tried to install a tach that did not "plug and play" Try finding a tach that will plug and play, call around to different Z shops, see if any have a used tach lying around.

okay thanks alot for the help, it was greatly appreciated

I began removing the tachometer and i realized that the signal wire was not even hooked up, infact is was just rolled up and tied to the dash, great all i have to do is hook it up right, i know that the green wire goes to the positive side on the coil, and that the black wire goes to a resister and then to the ignition switch my question is where is the hook up on the ignition switch and where is the resister that i must through?