Upgrade your 4.3L V6 engine with these performance Vortec-style cylinder heads, designed as a direct replacement for OEM casting #12557113. Manufactured from premium cast iron, these heads offer increased strength, improved cooling efficiency, and superior port flow for optimal performance. The assembled version includes OE-type valves, seals, valve springs, and retainers, ensuring a seamless installation. With a thicker deck to prevent cracking and hardened exhaust seats for durability, these heads provide OEM-quality performance with enhanced reliability. Fits various 4.3L V6 applications from 1992-2014, including trucks, SUVs, and vans equipped with a Vortec 8-bolt intake manifold. Ideal for engine rebuilds, stock replacements, and mild performance upgrades. Engine Quest produces high-quality OE-style replacement parts. Each part undergoes rigorous testing and inspections to meet EngineQuest's exact specifications. Designed for precision manufacturing and durability, our products ensure easy installation. With nearly 500 SKUs available, the company specializes in hard-to-find, in-demand parts, including those no longer available from the OEM, difficult to salvage, or with prohibitively high OEM costs.