Harmonic Balancer Bolt 12pt GM LS Gen III/IV

The Harmonic Balancer Bolt 12pt GM LS Gen III/IV by MOROSO is a precision fastener engineered for high-performance LS engine builds where reliability and proper clamping force are non-negotiable. This 12-point bolt secures the harmonic balancer—a critical component that dampens crankshaft vibration and protects your engine from destructive resonance frequencies. Whether you're building a street engine, track machine, or supercharged combination, this bolt delivers the OEM-grade holding power needed to keep your balancer locked in place under extreme conditions.

The 12-point design of this harmonic balancer bolt offers superior engagement compared to standard 6-point fasteners, reducing the risk of rounding and allowing for more precise torque application—critical when working with LS Gen III and Gen IV engines where factory specifications demand exact clamping loads. MOROSO fasteners are manufactured to strict tolerances using high-strength steel, ensuring consistent performance across repeated engine start cycles and high-RPM operation. The compact dimensions and 0.98 lb weight reflect the precision engineering typical of professional-grade engine components, with surface finish and threading quality that resists corrosion and galling during installation.

This bolt is essential for LS Gen III (2005–2007) and LS Gen IV (2008+) engine enthusiasts performing balancer replacement, timing chain service, or complete engine assembly. Proper installation requires following factory torque specifications and using a quality torque wrench to achieve the correct clamping force—under-torquing risks balancer slip, while over-torquing can strip threads or damage the crankshaft. When sourcing replacement fasteners for your LS build, choosing OEM-equivalent bolts like this MOROSO component ensures compatibility with your engine's harmonic balancer taper and eliminates guesswork during reassembly.