Fits: 361-383-400-426W-440 applications Specially designed gaskets are manufactured from 40 durometer rubber molded over and vulcanized to a rigid steel frame The extra-strength design will not leak, blow out or get sucked in like stock or inferior-quality aftermarket gaskets Superior quality rubber/steel gaskets outlast cork and rubber composite designs to provide years of dependable service, especially when constantly removing and reinstalling valve covers Full 3/16" thick 2 per package