A three line fuel system can be accomplished by drilling the third hole in the tank stopper. Use a brass tube on all three lines. Attach one end of some fuel line to one of the brass tubes and the other end of the fuel line to the clunk. Bend one of the brass tubes up for vent and bend the last brass tube down. Attach one end of some fuel line to the brass tube you bent down and the other end of the fuel line to a fuel filler dot, which should be attached to your cowl or fuselage. Attach one end of some fuel line to the brass tube you bent upward and the other end to the pressure fitting on the muffler. Lastly, attach some fuel line to the brass tube which has the clunk and the other end of the fuel line to the carb. When you defuel your plane, you do not have to set it on its nose nor will any lines get tangled in your tank. With a fuel filler dot, you will not have fuel lines hanging out either. It is a very clean installation. Good luck and happy flying.