ACDelco GM Original Equipment Engine Cylinder Head Gasket Kits include everything you need to replace your vehicle's engine cylinder head gasket, including the entire valve cover bolt assembly. The head gasket contains all the heat and compression generated by your vehicle's engine. It seals the combustion chambers and coolant and oil passages between the cylinder head and the engine block. These engine cylinder head gasket kits are GM-recommended replacements for your vehicle's original components. These original equipment kits have been manufactured to fit your GM vehicle, providing the same performance, durability, and service life you expect from General Motors.