Le Mans 4" Flip-Top Fuel Filler Cap. Note: Supplied with undrilled mounting flange which must be drilled to suit application. Mounting flange is 5-1/4" in diameter. Customer must also fabricate gasket between flange and car body. LeMans Filler Cap. This is a case where quality shows. What sets these apart are the details like a spring-loaded rubber gasket with a solid brass backing. The pins on which the cover hinges and the roller clasp operates are stainless steel. The spring for the clasp is, likewise, stainless. This with the alloy cast body nets a rust-free part.