You have an early gas tank and a later car. On '71-72 cars, that was the fuel-out line connected to the fuel pump inlet. In '73, the factory added a new tank sender that incorporates the fuel outlet, so the tank hole is plugged. You have a transition tank and there are advaltages! If you decide to boost the power of your car, the stock fuel line is too small in dia to support more than about 450 horses. But the second outlet on your tank can be teed to the pump and will support MUCH more than 450 hp. Second, if you ever decide to add EFI, the tank must be modified to provide a bypass fuel return... except on your tank, which already has a port for that. Lucky man!
