Upgrade your LS engine with the EngineQuest LS Cylinder Head Bolt Set, designed specifically for 1999-2003 LS1, LS6, LQ4, LQ9, and LM7 V8 engines. This complete kit includes all the bolts needed for both cylinder heads, ensuring a secure and reliable fit for your engine rebuild or repair. Crafted from high-quality steel, these torque-to-yield (TTY) bolts are engineered for single-use applications, maintaining proper tension and preventing head gasket failures. Compatible with GM part numbers 12558840, 12560744, and 12560745, this kit provides a direct replacement that meets or exceeds original equipment (OE) standards. Whether you're a professional mechanic or a DIY enthusiast, the EngineQuest LS Cylinder Head Bolt Set is the ideal choice for restoring performance and reliability to your LS engine. Key Features: Designed for LS engines (4.8L, 5.3L, 5.7L, 6.0L) from 1999-2003. Complete set for both heads, compatible with LS1, LS6, LQ4, LQ9, and LM7 engines. Manufactured with durable steel for high-strength performance. Torque-to-yield design for secure cylinder head sealing. Meets OE specifications for a perfect fit and hassle-free installation. Ensure your engine is ready to deliver peak performance with the trusted quality of EngineQuest.