SCE Gaskets Pro Copper Head Gaskets for Chevrolet Gen 5 & 6 Big Block

Pro Copper Head Gaskets for 1991 to Present Gen 5 and 6 454-572ci Big Block Chevrolet. Bore Opening: 4.630?; Gasket Thickness: .062?; Material: Annealed Copper. *Pro Copper head gaskets require O-rings in block or head* For Self Sealing Copper Gaskets to be used with O-rings please see Titan Head Gaskets. For Self Sealing Copper Gaskets to be used without O-rings, please see ICS Titan Head Gaskets. Package Contents: 1 Pair.