Replace the warped, cracked, or damaged Cylinder Heads and upgrade your 2003-2007 Ford 6.0L Powerstroke. Overheating caused by coolant loss or restricted coolant flow and head gasket failure is one of the most common causes of damaged to cylinder heads. If a cylinder head gets too hot it can warp or crack and require expensive machine work or complete replacement. When the metal is heated past normal operating temperatures, it expands past its limits. As it cools, the head often will not return to its original shape or size, instead settling into a more distorted or bent form. In extreme cases of overheating, the cylinder head can even crack and typically needs to be replaced. 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. Whether you are searching for stock OE-replacements or high-performance aftermarket cylinder heads find everything you need for your vehicle. For most applications you can choose between brand new castings or remanufactured heads in either cast-iron or aluminum. Available as bare heads or complete with the valvetrain installed. These fully loaded heads include upgraded valves, seals, retainers, locks, valve springs, as well as hardened seats and guides and are ready to bolt-on right out of the box. Performance heads feature upgraded intake and exhaust runners designed for more flow resulting in increased horsepower and torque. Other benefits can include better cooling and some even offer a weight reduction compared to stock. Shop all the top brands including ProMaxx Performance, Industrial Injection, Edelbrock, Diamond Advantage By Navistar, Ford, Powerstroke Products, Fleece Performance, and more!