Hello, thanks for the warm welcome. My question is: I have a 1971 Mustang in which I'm modifying the instrument pannel to a Mach 1, I have so far done the central instrument cluster and about to install a original used Tach. My question is how do I go abut wiring it. The tach. has only to black wires coming out of the back. Which goes to the ignition switch and which to the ignition coil?