Competition Cams 2135 Magnum Double Roller Timing Set for Ford 351 Windsor, '69-'84 Feature induction hardened cast iron camshaft gear and billet steel crank sprocket 3 Keyway crank sprocket for 4-degree incremental adjustability, 4-degree maximum advance/retard Heavy duty, heat-treated true double roller timing chain; chain available separately Ideal for mild street performance applications