This unique two-piece design fits all small and big block Chevrolet and Ford engines. They are made from 6061-T6 billet aluminum and feature a mirror finish and stainless steel hardware. The wire looms mount to the base of the valve cover with adjustable tabs. If you are using a center bolt application, youll have to purchase separately the late model bracket kit. These wire looms are for 8 millimeter wires. The looms measure 14-3/4 inches long by 2-1/4 inches wide.