Zanfyxil 12557840 Harmonic Balancer Bolt – 10.9 Grade Steel for GM Gen.3/Gen.4 LS Engines – LS1 LS2 LS3 LS6 LQ4 LQ9 4.8L–6.2L (Excl. LS7/LS9) –

Zanfyxil 12557840 Harmonic Balancer Bolt – 10.9 Grade Steel for GM Gen.3/Gen.4 LS Engines – LS1 LS2 LS3 LS6 LQ4 LQ9 4.8L–6.2L (Excl. LS7/LS9) –

OEM Fit & Reliable Replacement: Designed to match OEM part numbers 12557840 and 917-139 for a secure fit in GM harmonic balancer systems Broad LS Engine Compatibility: Works with Gen.3 and Gen.4 LS engines including LS1, LS2, LS3, LS6, L59, L92, L96, L99, LC9, LH8, LMF, LMG, LY5, LM7, LR4, LQ4, LQ9 (4.8L–6.2L). Not compatible with LS7/LS9 Durable 10.9 Grade Steel: Made from heat-treated steel rated Grade 10.9 for dependable performance under engine stress and vibration Dacromet Finish: Coated with Dacromet to support longevity in challenging engine conditions Simple Installation: Direct replacement bolt that installs easily without special tools. Ideal for DIY or professional use Product Description​ Upgrade your GM LS engine's harmonic balancer system with the Zanfyxil 12557840 Harmonic Balancer Bolt, a high-performance replacement designed for Gen.3 and Gen.4 LS series engines. Crafted from Grade 10.9 high-strength steel, this bolt delivers exceptional durability, surpassing OEM standards to withstand the rigorous demands of daily driving and high-performance applications.