This kit is for use with Gen VI BBC engines only. Installation requires the removal of an existing timing set for the installation of a new double row chain timing set (clearancing of the block may be required). For proper belt alignment, the balancer must be milled the thickness of the crankshaft reluctor. The 58x crankshaft reluctor/sensor and 4x camshaft sprocket/sensor produce crankshaft and camshaft signals compatible with Gen IV LS-Series ECMs (like E38 and E67 ECMs). Includes timing set, 58x crankshaft reluctor, timing cover with attaching bolts, CMP sensor w/ pigtail, and CKP sensor w/ pigtail.