Hi-Tech Roller Race Timing Set for GM LS Gen IV (58x) Applications, Single Chain 9 Keyway (Three-Bolt, 4 Pole Reluctor) features:9-keyway crank sprocket offering 8 degrees maximum advance/retard (16 degrees total)Single chain, full Roller timing sets offer an excellent performance upgrade from stockCast iron Camshaft Gear and induction hardened Steel crank sprocket increase durabilityDynamically balanced and quality checked for run-out tolerancesPre-stretched and heat-treated chains avoid further stretching or breaking, which can lead to timing errors or internal engine damageIdeal for all non-VVT LS street performance and Race Applications