There is something strange going on here. That wire wheel cover was available on Mustangs through 1970, in 14" only. They had the red center's as shown above. Ford didn't start putting 15's on Mustangs until 1969, and then only on the Boss 302's & 429's. Same for 1970. In 1971 the Boss 351's, and any model w/Magnum 500 wheels got 15's. All that being said, I'm thinking someone put that center piece on that 15' cover. Does it look like it has been tampered with on the back? I hate to ask you this , but are you sure it is 15"? All the wire covers like that I've seen were 14". F F