Copper Pre-Flattened O-Ring Head GasketSuit Chevy LS1-LS6, 4.135" Bore, .041" Compressed TthicknessBrand: FELPROPart Number: FE1041Description: These Fel-Pro wire ring head gaskets feature the same race winning construction as our steel o-ring gaskets but with a pre-flattened copper combustion seal to prevent brinelling of aluminium cylinder heads.