Got this car with fuel gauge not working. 305 TBI was swapped for a 350 with carb. I'm sorting out what was done to the car. Gas gauge doesn't work - pegged past full. Tach needle moves but mostly pegged to 7000. Car is an 86 but gauge cluster appears to be from at least an 88 - 115 mph speedo. I pulled up carpet in the back and hole was cut to access fuel pump/sender from inside without dropping tank. There is a plug? behind the rear seats where wires were cut and spliced and run under the carpet under the rear seats. Oh and motor now uses a mechanical fuel pump. I see three wires coming from pump area - brown, pink, and black. I want a functional fuel gauge. How can I wire up another fuel gauge?