Gasket Professor-”What’s the size of the groove hole in my block?”



Hello! I drive Subaru for race use only drag! I have pro SCE custom made head gasket 2mm thick ! Engine bore 97! My problem is we can’t figure out the size of groove hole in the block and receiver in the head and fire ring size !!! And what materials of fire ring do we have to use steel or copper? We took engine apart for many times due to problems of combustion sealing!

Gasket Professor Answer-

Dear Alex,
· You should use .041” diameter 304 Stainless wire for the o-ring.
· O-ring Groove Dimensions:  .039” wide x .026” deep
· Receiver Groove Dimensions: .060” wide x .012” deep
Carefully follow these specifications and you will have the best possible combustion seal for the Subaru EJ head bolt pattern.