Spectre's timing tabs have an adjustable timing pointer to allow for a more accurate reading and they can work with any size harmonic balancer. Designed for Chevy small block engines, Spectre's adjustable timing tabs have a polished aluminum finish so it will look great under your hood. Product Features:Polished aluminum finishDesigned for Chevy small block enginesAdjustable pointer allows for use with 6, 7, and 8 In. harmonic balancersInstalls easily where original tab mounts