For 1967 or can be used on 1964-66 if converting to a dual reservoir master cylinder. Block mounts to the frame and the single master cylinder line screws into the top while the left and right front screws to the sides and the front to rear screws into the back. Blocks are often discarded with the old lines. Correct size, shape and thickness. Fits 1964-67 Cutlass,Chevelle/El Camino, GTO, Skylark