Crank Hub & Inner Shell Steel - BBC w/1/4 Keyway

The ATI Performance Crank Hub & Inner Shell Steel for BBC with 1/4 Keyway (SKU ATI916890K) is a precision harmonic balancer hub assembly engineered for big block Chevy engines. This inner shell component features black oxide steel construction, designed to absorb and dampen crankshaft vibrations that occur at engine operating speeds. Proper harmonic balancing is critical for reducing stress on engine bearings, extending crankshaft service life, and maintaining smooth operation under sustained load.

The 1/4-inch keyway specification ensures secure, indexed mounting to the crankshaft without slippage. Black oxide finish provides corrosion resistance in high-heat engine bay environments. Weighing 3.75 lbs with compact dimensions (5.3 x 4.6 x 5.5 inches), this inner shell integrates as a core component within ATI balancer assemblies. Steel construction offers the durability and dampening characteristics required for high-performance and heavy-duty engine applications where aluminum alternatives may not provide sufficient resonance control.

This component is suited for engine builders, performance shops, and enthusiasts rebuilding or upgrading big block Chevy powerplants. Whether for street performance, racing, or marine applications, selecting the correct harmonic balancer geometry and material composition directly impacts engine longevity. ATI Performance's reputation in the balancer market reflects years of focused engineering on vibration management. This inner shell replacement or upgrade component allows builders to install a complete, matched harmonic balancer system that meets OEM fitment and performance standards.