Competition Cams 3138 Hi-Tech Roller Race Timing Set for 5.0L, 351 Windsor Ford, &#39;84-&#39;92 Cast iron camshaft gear and induction hardened billet steel crank sprocket Features 3 keyway crank sprocket for 4-degree incremental adjustability, 4-degreemaximum advance/retard Pre-stretched, heat-treated double roller chain with heavy-duty large pin design; chain available separately Dynamically balanced and quality checked for run-out tolerances Ideal for all street performance and race applications