This is a new pair of Chromed Aluminum Ball Milled Tall Valve Covers for 1958-86 small block Chevy. Fits 1958-86 small block Chevy 283, 302, 305, 327, 350 heads with perimeter bolt pattern. 1-1/4 breather hole per cover. 1958-86 283, 305, 327, 350 Small Block Chevy. 1987-95 Pontiac Firebird and Chevy Camaro with 350.