6-3/4" Harmonic Balancer Cover Chevy S/B Billet Look. This patented harmonic balancer cover offers improved readability, more stable Top Dead Center indication and timing accuracy, enhanced appearance for a previously ignored underhood area, and the elimination of timing tapes which are inevitably flung off. It is distinctively marked with Top Dead Center and the proper timing degrees.
Using this cover improves timing accuracy because over time the etched outer inertia ring of a typical harmonic balancer may slip in relation to the center hub of the balancer, causing the etched markings to provide an inaccurate indication of Top Dead Center for the #1 piston. Mounted directly through the center hub, this cover eliminates the affect of any outer inertia ring slippage. Aluminum. U.S. Patent 5,675,078.
