69 GTX with repro tank and fuel sender assembly from year one. 3 questions: There are two nipples on the top of the fuel quantity/float assembly. One is connected to the fuel line that feeds the engine. What is the purpose of the other? There are two vent lines connected to the forward edge of the fuel tank on the drivers side. One line goes straight up, curles, and ends under the car. The second line goes into the trunk, snakes around the trunk and goes back through the trunk to the underside of the car just forward of the right real wheel. What is the purpose of this line? I cannot find the end of the line from under the car. Finally, does it matter which nipple on the sending unit I attach a ground wire to? Or should the wire be attached to the nipple that supplies the fuel line to the engine.

The two lines on the sending unit are 3/8 fuel supply and 1/4 fuel return. In 69 there should be only 1 vent line. That's the one you see going into the trunk. Plug the other. That tank being aftermarket was made to fit multiple years.

My orignal 69 runner had the two vent lines, one into trunk and back out into rail and the short one that clipped onto shock crossmember. Orignal gas tank.