I recently installed a new set of Sport Comp gauges in my 64. Everything went fine except for the gas gauge. The gauge dial didn't move. I installed a new sending unit thinking it went bad. Then I was told that the gauge might not be the right ohms. I ordered and installed a 0-30ohm gauge and now as soon as the ignition is turned on, the gas gauge goes past full. I'm stumped. I've tried different grounds. Any suggestions would be greatly appreciated.