We were watching the MCA judges in the '65 concours class and overheard a conversation about the '6411/42 gas caps. We checked all the cars in the class and couldn't determine any differences-they all looked the same to us. I've always heard that there were differences between the '6411/42 and '65 versions; what are they? I want to find an N.O.S. cap for our restoration.Bob and Jack FullmerLexington, KY
The early '6411/42-'65 Mustang gas cap was Ford PN C5ZZ-9030-A. The later '65 gas cap was PN C5ZZ-9030-B. They're identical with the exception of the antitheft strap added to the later cap. I've included an illustration of the later one from an original installation sheet.
Unless you remove the cap from the car, it's fairly difficult to see the strap. If you remove the strap from a C5ZZ-9030-B cap, the hole in the base shows, so it's still incorrect for an earlier car.
An N.O.S. C5ZZ-9030-A cap is a rare find. You might keep watch on eBay.