Tach likes to read less than 0

olddman said

Green wire from tach to negative side of coil is getting current when ignition switch is in run position. Red wire from tach going to ignition switch getting current. White wire from tach connected to dash lighting getting current. Black wire grounded. Have checked all connections and all is tight.

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Just to get this out of the way, some tachs are voltage driven and some are current driven.
IIRC Autogage uses one and Autometer the other. I think this only mnalkes a difference when converting a pulse like one would get from an MSD 6 tach output. But maybe I'm missing or forgetting something.

One test you can make is with a hand held tune up type tach. See if that works.

Green wire is the pickup signal, and yes normally that goes to the negative side of the coil.
The negative side of the coil should not be continously seeing current. In fact I don't know how you are measuring current.
Much easier to measure presence of power (voltage). Voltage on the negative terminal should fluctuate with points opening and closing.