One more question...

The otc 2000 displays RPM lower than the dash gauge...when OTC says 2k, dash says about 3k. I believe the otc, cuz dash says redline on acceleration when I know by the sound of the engine it'* not wound that tight...

Hard to see inaccuracy at idle, but definitely gets worse with increased RPM...

Is there an easy fix for inaccurate tach, or is replacement time???

Thanks again

Does it seem to shift at the proper actual RPM?

Yup...shifts and behaves normally, tach is just wrong.

Sounds like a calibration error, probably a trim resistor though have not had one of them apart. Might be easiest to just replace if you cqan find another.