Wanted: Replacement tach and Volt Gauge

[jeffs98]

I have an 82 C-70 dump truck and need a replacement tach ( it does not work) and a volt gauge as well!! Any GOOD used ones or a place to get reasonable new ones would be Greatly appreciated!! Thanks!! Also, if anyone knows what kind of voltage should be at the gauges and how the wiring ties in to the gauges that would be appreciated too!! I would really like to purchase a wiring schematic or like to know where to view one on line!! AGAIN, thank you!!