1967 Dodge Dart gauges

I have a 1967 Dodge Dart GT I recently bought. The water temp and fuel do not work. I have replaced them and replaced the circuit board still nothing. I have replaced the gauges, circuit board, sending unit in the tank, the voltage regulator on the circuit board, the sending unit in the intake manifold, the latest trick is the fuel gauge needle moves from empty to full like a windshield wiper. I have also added two ground wires to the circuit board and secure them to the steering column. Any help would be appreciated. Thanks.