ICT Billet Harmonic Balancer Crankshaft Pulley Bolt for GM LS/LT 5.3L–6.2L — OEM‑Spec, Made in USA (Single)

ICT Billet's 551218 harmonic balancer crankshaft pulley bolt is a factory-spec replacement bolt designed for GM Gen III–V small-block engines, ensuring correct clamping and service compliance.

When you remove and reinstall the harmonic balancer on GM's LS/LT family, GM specifies replacing the balancer bolt each time — this ICT Billet part meets that requirement by offering a genuine OEM bolt made in the USA and sold individually. It fits a wide range of 5.3L, 6.0L and 6.2L engines across many LS-series castings (excluding LS7/LS9 and LT4/LT5), providing the correct thread, head size, and torque characteristics to secure the crank pulley reliably.

What vehicles and engines will this bolt fit?

This bolt is compatible with most GM Gen 3, 4, and 5 V8 small-block engines, covering many LS and LT variants used in trucks, performance cars, and crate engines. Confirm fitment against your engine code or casting to avoid the excluded models.

• Compatible with LS1, LS2, LS3, LS6, LQ4, LQ9, LM7, LM4, L33, LH6, L92, L76, LY2, LY5, LY6, LC9, LFA, LH8, LMG, and others.
• Fits common displacements: 5.3L, 6.0L, 6.2L where a balancer-bolt replacement is required.
• Not suitable for LS7, LS9, LT4, or LT5 applications.
• Sold as a single replacement bolt — purchase quantity accordingly.

Why use this OEM-style bolt instead of reusing the original?

GM service guidelines require a new crank bolt when reinstalling the balancer because the bolt undergoes torque stretch and clamping load changes. Installing a new ICT Billet OEM-style bolt restores correct preload and reduces the chance of loosening or failure under load.

• Meets OEM specifications for strength and thread engagement.
• Restores intended clamp force after disassembly and reinstallation.
• Reduces risk of balancer wobble or bolt loosening during operation.
• Manufactured in the USA for consistent quality and traceability.

How should I install this bolt to ensure proper torque and safety?

Installation requires following GM torque specs and sequence to tighten the crank bolt correctly; using a calibrated torque wrench and, where specified, an angle gauge is essential. Tighten to the factory-specified torque and, if required, the published additional angle to achieve correct bolt stretch.

• Use the factory-recommended torque value and angle measurement if specified.
• Replace any damaged washers or threads before install.
• Inspect crankshaft snout and balancer for damage or wear prior to reassembly.
• Always follow vehicle service manual procedures for safety.

What makes ICT Billet’s 551218 bolt a reliable purchase?

This item is a genuine GM-spec bolt, manufactured in the United States and sold individually for accurate parts replacement. It’s produced to meet the mechanical properties and tolerances expected for high-load crankshaft fastening tasks in modern GM small-block engines.

• OEM-compliant design ensures proper fit and function.
• Made in the USA for consistent materials and manufacturing control.
• Sold individually so you can replace exactly what's needed.
• Works across numerous LS and LT engine variants for broad applicability.

Who is this for? This replacement bolt is intended for vehicle owners, mechanics, engine builders, and restorers working on GM Gen III–V small-block engines who want a compliant, high-quality OEM-style replacement after disassembling the harmonic balancer. If you’re servicing or rebuilding an LS/LT engine (except the excluded models) and need to meet GM service requirements, this ICT Billet 551218 bolt is a straightforward, dependable option.