Replace the warped, cracked, or damaged Cylinder Heads and upgrade your 2007.5-2010 Chevy/GMC 6.6L LMM Duramax. The most common failure of cylinder heads is due to overheating, which can be caused by coolant loss or restricted coolant flow and head gasket failure. When a cylinder head gets too hot it can warp or crack and require extensive machine work or replacement. When a head is heated past normal operating temperatures, it expands past its limits. As it cools, the head often will not return to its original size or shape, instead settling into a more bent or distorted form. In extreme cases of overheating, the cylinder head can crack and typically needs to be replaced. Find everything you need for your vehicle whether you are searching for factory OE-replacements or performance aftermarket cylinder heads. Both remanufactured heads and brand-new castings are available in either cast-iron or aluminum construction. Offered as bare heads or complete with the valvetrain installed. These fully loaded heads are ready to bolt-on right out of the box and include upgraded valves, seals, retainers, locks, valve springs, as well as hardened seats and guides. High-performance heads are designed to increase flow for more horsepower and torque. Other benefits can include improved cooling and even a weight reduction compared to the stock heads. Fire Rings or O-Rings are offered for mild to high performance engine builds. A cylinder head with a fire ring has a small groove machined around each combustion chamber. A metal ring or hoop is then inserted into it. The ring creates an additional seal that contacts the outer edge of the fire ring in the head gasket. This helps provide a better seal around the combustion chamber. A cylinder head with a machined fire ring ensures greater reliability under extreme stress. This is especially ideal for higher horsepower diesel applications. Shop all the top brands including ProMaxx Performance, Industrial Injection, Edelbrock, Diamond Advantage By Navistar, Ford, Powerstroke Products, Fleece Performance, and more!