I searched the subject and found some info but not exactly what I’m looking for. 1970 442 and somebody at some time swapped rally pack gauges in it. The wiring was as changed as per the diagrams I found. The issue I’m having is no key on the oil gauge reads a little below 1/2 or so. As soon as I turn key to on it pegs high. Running it makes no difference still max high. Turn key to off and it rests back around under half. The water temp and fuel gauge work fine as does the gen light. Bad sending unit? Wire grounding somewhere between gauge and sending unit?

 

I also tried unhooking the wire from sending unit and also grounding the wire. All acts the same