Kelsey-Hayes 4 piston discs were available on an A body starting in 1965, I believe, 66 for sure. They were used all the way up through 72 when the rim bolt pattern was changed to 4.5". Also available on B body cars through 69 with the large bolt pattern. If you think the A body stuff is hard to find, try finding anything for the B body setup. YIKES!!! Geof