I was just wondering if it is possible to wire a Autometer tach from the back of the gauge cluster?

There are 3 wires on the back of the Autometer tach: black, yellow, and green.

For the green wire, I can splice it to the blue wire on the black of the gauge cluster. Where can I connect the yellow and black to on the back of the gauge cluster?

 

Yes it's possible. the tach signal hooks up to the blue wire, and for the rest, use a voltmeter to determine which one is switched power, and which one is constant. I used the guage cluster wiring for the light on the tach, and the tach signal, for the constant power, I used the radio wiring. I would reccomend tapping the blue wire into the distributor itself, as it is more accurate. I'm probably going to do this eventually.

 

unless you have an old or lower model tach from autometer the wire colors should be red for power, black for ground, green for tach signal and white for illumination.

 

like the post above it's from the left hand side plug its the blue wire white st. i think its the 2 nd from the end