Abstract: In a two piece valve assembly comprising a non-weldable lower valve body portion inserted into the fuel tank through an opening in the tank wall, and an upper valve body portion or cover made from a weldable material and designed to be connected to the lower valve body portion and welded to the upper surface of the fuel tank wall, an improved assembly structure comprising a plurality of circumferentially-spaced support/retention tabs formed on the upper end of the lower valve body portion to provide a self-supporting option for the lower valve body so that it may rest with the tabs on the upper surface of the fuel tank when inserted into the fuel tank opening, and/or further to be securely sandwiched between the upper valve body/cover and the upper surface of the fuel tank wall when a weldable portion of the cover is welded to the tank and melts over the tabs, thereby strengthening the connection between the upper and lower valve body portions.