74 dodge dart gas cap
Cali Dart,
Not 100% if this will work on your car or not, but if you wanted to switch to a flip-style gas cap you could PM 4mulaSvaliant and pony up some $$ the adapter and change it over to a flip-style one. They sell on here quite a bit. Looks real clean too!
http://www.forabodiesonly.com/mopar/showthread.php?t=53282&page=23