Pro Copper Head Gaskets for Donovan 417 Hemi. Bore Opening: 4.200"; Gasket Thickness: .043"; Material: Annealed Copper; Package Contents: 1 Pair. These gaskets are the same basic pattern as the 392, but the bores are larger than a stock block Chrysler can be bored to accept, they also have larger holes in the center 6 stud locations to allow for ring dowels.
SCE Pro Copper Head Gaskets are the standard of the industry, these are the gaskets that seal metal shredding 8000hp Top Fuel engines, Top Alcohol and Pro Mod Nitrous or Alcohol powered monsters. Though "standard" copper head gaskets may seem low tech, there are critical steps required for dependable performance in the land of giant horsepower. SCE begins with 99% pure copper sheet, rolled to our specifications. Each sheet is inspected to insure flatness so the cylinder head will have uniform contact across the sealing surfaces. Inferior brands using cheaper material will result in a high incidence of "torched" gaskets and heads. After processing SCE copper gaskets are annealed to insure a malleable gasket which conforms to the mating surface providing measurable gains in cylinder sealing, evidenced by lower leak down percentages.
