A harmonic balancer is a rubber bonded assembly, and rubber ages whether the engine runs or not. Once the outer ring has crept the timing mark lies to you and the crank loses its damping, so replacing it during a rebuild is cheaper than trusting a forty year old one. This is a new OE replacement rather than a cleaned-up core.

Proform 66511 OE Replacement Harmonic Balancer Features:

• Fits small block and Big Block Chevy engines.
• For internally balanced engines.
• Rated to 6000 RPM.
• Brand new assembly, not a rebuilt or refinished core.
• Accepts Proform balancer covers for a finished look.
• Sold individually.