From what i can tell, the chevy rally wheel actually was a BUICK wheel first. It was used on skylarks in 1966, with a different center cap, and the wheel was painted body color. It was first used by chevrolet in 1967, the wheel was put on production chevies until 1977. There were many versions of it, ranging from 14x5" to 15x8" The flat style "disc brake" cap was only used in 67, and was the only year it was used. There was also a "non disc brake" cap used in 67 on drum brake cars, that was the same cap, but just read "Chevrolet motor division" and didnt say "disc brakes" on it. In 68 the common "derby" style cap was introduced and the smaller disc brake style cap was discontinued from production. The derby cap was used then from 1968-1977 on lots of chevy models, including the chevelle, corvette, impala, el camino, monte carlo, camaro, and nova.