Why you need this tool - Removes and installs harmonic balancers and crankshaft pulleys reliably on Chevy SBC small block and Big Block engines. - Saves time and reduces the risk of misalignment or damage when working on crankshafts. - Compact, simple toolset for professional shops and DIY mechanics. Key benefits - Direct fit for Chevy SBC small block and Big Block crankshafts — replaces Part Number 66515. - Dual-thread design (5/8 inch-16 and 7/16 inch-16) fits a wider range of crankshaft bolt patterns without adapters. - Made from high-hardness carbon steel with heat treatment for improved strength, structural stability, and long service life. Corrosion- and wear-resistant for repeated use. - Simple 3-step installation minimizes fuss and speeds jobs: insert, assemble, tighten. - Includes all required parts for a single, hassle-free operation. Specifications - Compatibility: Chevy crankshafts — SBC small block and Big Block. Replaces Part Number 66515. - Thread sizes: 5/8 inch-16 and 7/16 inch-16 threaded ends. - Material: High-hardness carbon steel, heat-treated. - Finish: Corrosion-resistant, wear-resistant. - Kit contents: 1x Threaded Rod, 1x Nut, 1x Washers and 1x Thrust Bearing. How it solves common problems - Removes balancers without relying on improvised methods that can damage crank snouts or threads. - Dual-thread ends let you select the correct thread engagement for the crankshaft, avoiding stripped threads and ensuring steady pulling force. - Heat-treated carbon steel construction holds up under repeated torque, avoiding tool deformation during installation or removal. Easy 3-step installation (lubricant recommended) 1. Apply a light lubricant to threads for smooth operation. 2. Insert the threaded rod into the designated crankshaft position and assemble the thrust bearing, washers, and nut in order. 3. Tighten the nut securely with a wrench until the balancer is seated or removed as required. Typical applications / use scenarios - Replacing a harmonic balancer on a Chevy small-block V8 during an engine rebuild. - Removing a stubborn crankshaft pulley while performing timing chain or front seal service on a Big Block Chevy. - Routine maintenance in a home garage or professional shop when inspecting or swapping accessory drive components. What’s included - 1x Threaded Rod - 1x Nut - 1x Washers - 1x Thrust Bearing Notes and best practices - For optimal performance, use a light lubricant on threads before operation. - Use appropriate torque and steady pressure when tightening to avoid overloading the crankshaft. - Verify thread size and fit on your specific crankshaft before use. Durable, straightforward, and compatible with Chevy SBC small block and Big Block engines, this harmonic balancer installer bolt replaces Part Number 66515 and provides a reliable solution for balancer removal and installation.