New Pair Loaded Duramax 6.6L GM Chevrolet Silverado Sierra Cylinder Heads LLY W/ Head Gasket Set & Bolts, Water Pump & Timing Set

Enhance the power and durability of your GM Duramax 6.6L engine with our premium pair of loaded 6.6 Duramax LLY cylinder heads, complete with a timing kit and water pump for a comprehensive engine upgrade. Designed for Silverado and Sierra models, these heavy-duty aftermarket cylinder heads are built to meet or exceed OEM specifications, ensuring long-lasting performance under the toughest conditions.

Each set comes fully assembled with valves, springs, and retainers, ready for seamless installation. Plus, with the included timing kit and water pump, you get everything needed to maintain proper engine synchronization and cooling, extending engine life and optimizing efficiency. A core return is required for this purchase.

Key Features:

• Heavy-Duty Aftermarket Casting – Manufactured with a robust design that offers superior strength and resistance to cracking compared to factory heads. The thicker casting withstands high pressure and extreme temperatures, making it ideal for heavy-duty applications.
• Loaded & Ready to Install – These cylinder heads come pre-assembled with high-quality valves, springs, and retainers, ensuring optimal airflow, improved combustion, and maximum engine efficiency.
• Precision Engineering for a Perfect Fit – Designed to match OEM specifications, ensuring reliable performance in GM Duramax 6.6L LLY engines. Precision-machined valve seats and guides provide enhanced durability and optimal sealing, preventing leaks and reducing wear.
• Complete Set: Includes head gasket set & bolts, water pump & timing set for peak performance and longevity
• Fits GM Silverado & Sierra 6.6L Duramax LLY Models – Engineered for a perfect fit and easy installation in 2004.5–2005 Silverado and Sierra 2500HD/3500HD trucks equipped with the 6.6L Duramax LLY engine.

Benefits:

• Enhanced Performance – Thick casting and premium components improve sealing, heat dissipation, and airflow for more power, fuel efficiency, and lower emissions.

• Built to Last – Reinforced casting and high-strength materials ensure long-term durability, reducing the need for repairs or replacements.

• Easy Installation – Fully assembled for a precise, hassle-free fit, minimizing downtime and getting your vehicle back on the road faster.

Why Choose Our Duramax 6.6L Cylinder Heads?

Choosing our heavy-duty aftermarket LLY cylinder heads means investing in quality, durability, and performance. Engineered to address common issues with factory heads, such as cracking under pressure, these heads are the perfect upgrade for your Silverado or Sierra. Backed by our commitment to providing premium products, these cylinder heads will keep your engine running smoothly for years to come.

Heavy Duty Parts Company – Core Returns Policy

At Heavy Duty Parts Company, core returns are essential to our ability to provide high-quality, cost-effective cylinder heads to our customers. These returned cores supply essential components, such as keepers, springs, and retainers, which are critical to engine performance.

No Core Charge – Just Send It Back!

Unlike other companies, we do not charge a core fee upfront. Instead, we rely on our customers to return their used cores to keep our supply chain running smoothly.

Why Core Returns Matter

• Many small but essential parts from cores are reused to maintain OEM-quality cylinder heads.
• Returning cores keeps prices competitive by reducing the need for costly new components.
• It supports sustainability by minimizing waste and conserving resources.

Send Back All Components

To ensure the quality and integrity of our remanufacturing process, we ask that you return all components that were originally included with your new cylinder head. This includes items such as:

• Rocker arms
• Camshafts (if applicable)
• Any other hardware that came with your purchase

Easy & Free Core Return Process

• Each purchase includes a prepaid core return label in a plastic sleeve on the box.
• Simply pack your core with all included components, attach the label, and drop it off with the carrier—no extra cost to you.
• Returned cores undergo inspection and recycling, ensuring maximum efficiency.

Customer Partnership & Sustainability

By returning your core and its components, you help maintain a reliable supply chain, ensuring we can continue offering top-quality products at the best prices. This process not only benefits your wallet but also contributes to a greener and more efficient automotive industry.

We appreciate your support in keeping our business and the industry running smoothly!

Shipping Information

We ship exclusively to the lower 48 states. Insurance, packaging, and handling are included in the shipping cost to ensure safe and secure delivery.

Warranty Information

Our cylinder heads are backed by a two-year unlimited mileage parts warranty. The warranty covers parts only and does not include labor or incidental costs. To maintain warranty coverage, the heat tab must remain intact and unaltered.

Contact Us

For more information or assistance, visit our website and explore our extensive selection of high-quality cylinder heads and engine components at Heavy Duty Parts Company.

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Duramax 6.6 LLY