2004.5-2005 LLY Duramax Premium Stock Plus Cylinder Heads (RH & LH Set)

Restore factory performance and long-term reliability to your 2004.5–2005 LLY Duramax 6.6L with these stock remanufactured cylinder heads. Built to OE specifications and professionally remanufactured, these heads are designed to provide dependable performance for stock rebuilds and mild performance applications.

Each cylinder head is thoroughly inspected, pressure tested, cleaned, and precision machined to ensure proper sealing, airflow, and durability. Whether you're replacing worn or damaged cylinder heads or refreshing your engine during a rebuild, these Premium Stock Plus heads offer a reliable solution built to last.

Key Features

• Stock remanufactured LLY Duramax cylinder heads
• Fully cleaned, pressure tested, and resurfaced
• Diamond honed valve guides
• Unshrouded valves for improved airflow
• High-strength, heat-treated iron-based valve guides
• Premium nickel-based, non-magnetic valve seat inserts
• Multi-angle valve job
• New valve springs installed
• Assembled and ready for installation
• Ideal for stock replacement or mild performance builds

Premium Stock Plus Remanufacturing Process

Every Premium Stock Plus cylinder head is professionally remanufactured using strict quality control standards. Each casting is thoroughly inspected, pressure tested, resurfaced, and machined to restore proper sealing and performance. Critical valvetrain components are renewed or upgraded as needed to ensure long service life and dependable operation.

The result is a cylinder head that delivers OE-style performance and reliability while incorporating premium machining processes designed to maximize durability.

What's Included

• Left and right remanufactured LLY cylinder heads
• Fully assembled and ready to install

Not Included

• Gaskets
• Head bolts
• Injectors
• Installation hardware

Vehicle Fitment

2004.5–2005 GM Duramax LLY 6.6L

• Chevrolet Silverado 2500HD
• Chevrolet Silverado 3500HD
• GMC Sierra 2500HD
• GMC Sierra 3500HD

Why Choose These LLY Reman Heads?

• OE-style performance and reliability
• Professionally remanufactured and quality checked
• Premium machining and valve seat upgrades
• Ideal for stock replacement or preventative engine refreshes
• Built for long-term durability and dependable service

Core Return Information

Sold as a matched left and right pair.

To receive full core credit, a good, reusable pair of LLY cylinder heads must be returned. Cores must be free of cracks, excessive warping, or severe damage. Core returns are required within 90 days of purchase.