Replace the heads on your performance built 2008-2010 Ford 6.4L Powerstroke with the Powerstroke Products Loaded Stock O-Ring 6.4L Cylinder Head PP-6.4HeadLOEM-O. This O-Ringed cylinder head is designed to keep compression in the combustion chamber, and out of your cooling system. O-Ring heads are ideal for use on street/race applications and are designed to work with a standard head gasket. Each head is built from a new casting and is assembled with brand new valves, seals, and springs. No core required, sold individually.