I got a '68 Mustang fastback at the beginning of the summer; when I first bought it, when I would fill it up the needle would go past full, take forever to move to the 1/2 full mark, and then would go really fast from the 1/2 full to empty mark. After pulling the engine this summer, putting a Mass-Flo EFI kit on the car, and having an AN fitting welded onto the end of the sending unit, it does almost the opposite; when the tank is completely full, it will only read 3/4 full, although it seems to decrease much more steadily now. Does anyone know anything about this? Is my gauge broken, or is the sending unit bad? Does that even have anything to do with it? By the way, in case it matters, it's a 16 gal. tank. Thanks!