Check the listing for details. GM LS SFI Certified High Performance Harmonic Balancer. Condition: New. Listed at 246.99 USD. High Performance Design: Fits most GM LS engines and meets SFI 18.1 certification standards for high-RPM performance and racing reliability., Improved Efficiency: 30% more efficient above 5,000 RPM compared to stock dampers, freeing up horsepower and enhancing engine responsiveness., Precision Machining: CNC-machined shell mounts directly to the crank hub, ensuring timing marks remain in the correct position under extreme conditions., Rebuildable Construction: Features an inertia ring and hub design that can be rebuilt by replacing the elastomer strips as needed for continued performance., Maintenance Indicator: Exposed inertia weight at TDC provides a clear visual signal when the elastomer strips require replacement to maintain proper function.