Ultra-Seal Valve Cover Gaskets Fits Chrysler 1964-1969 273, 1967-1991 318, 1968-1973 340, 1971-1992 360 Mr GasketUltra Seal is Mr. Gasket premium valve cover Gasket material. It's manufactured from a high density cork and rubber blend with a black latex coat applied to the outside to help seal minor flange irregularites and eliminate oil leakage. It creates a positive seal by controlled swelling of the Gasket material when exposed to hot oil. For original equipment replacement, high performance street, drag race and oval track use. Sold as a pair, these Gaskets