1971 specific gas cap
Bryan, you might look up and include the assembly date of your car. I found out the hard way that not all 1971 Duster gas caps are the same. There was a change to the fuel filler neck during the production year and that resulted in a change to the gas cap design that was carried over into the 1972 production year. The 1972 type and later are easy to find. The early production run caps are more scarce and cost more if you find one. Good luck.