GoodyearŽ racing inner tubes in the 1960s were provided with military specification metal valve stem caps like you might also find in some aircraft landing gear wheel systems and with industrial hydraulic accumulator assemblies. Shelby American and Ford Advanced Vehicle used predominately Goodyear brand racing tires and racing duty inner tubes. The bright yellow painted caps on new Goodyear racing inner tubes were common for both organizations and were made by SCHRADERŽ.
Inner tubes made in America had caps that were marked as being made in the U.S.A., while inner tubes made in England had caps marked with that country of origin.
This "U.S.A." cap below was installed in a new Cobra with Goodyear race tires in 1963.
After initial installation the caps could have been lost during racing or just replaced during routine tire changes as well used race cars from either organization were seen with no caps or plain black plastic caps.