Accu Seal Pro Steel Core Valve Cover Gaskets for Chrysler 426 Hemi. This material is accepted for NHRA Fuel classes requiring steel core gaskets. These gaskets have 1/4″ bolt holes and cut out for down nozzle fuel rail fitting. Compare to Fel-Pro 1629, Mr. Gasket 384. Material; Steel Core Composite, Teflon Coated on One Side; Thickness: .080″; Package Contents: 1 Pair.