Eagle tachometer work with GM HEI distributor?

[priya]

I bought a used Eagle tach that is supposed to be in working order but its not working now that everything is hooked up.  Hubby checked and there is power to the tach power wire but he was wondering if the factory eagle tach is perhaps not compatible with the signal put out by the GM HEI distributor.  As well, he was wondering how the tach is ground seeing as we only have the yellow and green wire on the back of the tach hooked up.  Does it ground by being screwed into the instrument cluster or is there supposed to be a ground wire attached to it?

[ammachine390]

The stock Eagle tachometer only had 2 wires. One is switched positive 12 volts and other plugs into the tach signal (negative post) of the ignition coil. So the tachometer grounds through the ignition system. Unless the tach signal plug on the gm ignition is somehow different from the negative side of the ignition coil, then it should still work with the gm system.

[priya]

Thanks guys.