Fits Chevrolet small block stamped valve covers. Easily dropped into position, these revolutionary one-piece holddowns are fast to install, eliminating fumbling with four separate flange reinforcement clamps. By applying additional downward pressure nearer to the valve cover ends, this popular invention minimizes the possibility of oil leakage. Fits 1955 to 1986 262-400 Small Block Chevy Engines. Sold in pairs. U.S. Patent No. 4,821,699. Same as 66291 hold-downs, but with the added advantage of attached linear wire-looms for even more efficient installation.