1. Compatibility: Our harmonic balancer installer bolt is compatible with Chevy crankshafts of SBC small block and big Block, ensuring fit for your car engine installation needs. Replace Part Number 66515 2. Thread Specifications: Features 5/8 inch16 and 7/16 inch16 threaded ends, making it adaptable for more car engine crankshafts 3. Premium Material: This balancer crankshaft puller tool is crafted from highhardness carbon steel, undergoes heat treatment for enhanced durability, and features excellent structural stability. Its corrosionresistant and wearresistant properties ensure a long life 4. Easy 3Step Installation: For optimal operation, applying lubricant is recommended. First, insert threaded rod into the designated crankshaft position; Second, mount bearing/washers/nut in order; Third, tighten the nut securely using a wrench 5. Includes: 1x Threaded Rod, 1x Nut, 1x Washers and 1x Thrust Bearing. Everything you need for a quick, hassle installation