Andy, did you upgrade the tach and clock? If so RTE has a tach exerciser that swings the tach from zero to full scale continuously. It also calibrates the tach at 1000/4000 rpm. I have an exerciser that does this but live in Western Canada. Also you can hook 12 v to your gauges but make sure you are on the correct terminal. Then you can ground out the oil, gas and temp gauges, on the sensor connection terminals, to watch them go to full scale.