im doing the gas tank pickup, and after reading looking at the tread im not sure about the fuel guage, what do you do with the two black wires do you need either to make the fuel meter work, is one a ground wire. for the fuel guage

 

Is your gas gauge not working? My LG4 (carb) gas tank has two wires. One grounds the sending unit and the other connects to a potentiometer (0-90ohm variable resistor). The connection is a weathertight connector directly above the rear axle. You could probe the gas tank end to measure the resistance of the sending unit. You could also insert a 90ohm resistor on the car side, then short it to simulate full and empty.

Hope this helps.