[78trk]

I have a 78 with 2 tanks. I used a switch and wiring connector for a 81-87 w/carb. from Chevrolet. The after market switches seem to come apart to easy. Enlarge the hole for newer style switch and add a ground wire to switch.
I used a 81-87 6 port fuel tank switch.
I used the existing hot wire to the input of the old switch and that switched one tank on the fuel tank valve and I added another wire to the output of the switch to switch the other tank on the valve.
I attached the gas tank sensor wires to the fuel tank valve.
The new momentary fuel tank valve is a much better valve and after the dash switch switches tanks it shuts off power to the valve.