Cylinder Heads

This 14mm/12mm head stud kit from RCM uses aircraft-grade S99 steel studs to replace the standard 11mm Subaru head bolts, offering higher tensile strength and clamping force. Source material describes it as suited to higher-output EJ20/22/25 builds.

This 14mm/14mm head stud kit from RCM uses aircraft-grade S99 steel studs to replace the standard 11mm Subaru head bolts, offering higher tensile strength and clamping force. Source material describes it as suited to higher-output EJ20/22/25 builds.

This Extreme 11mm head stud kit from RCM (reference RCM1540) uses aircraft-grade S99 steel studs with a manufacturer-stated tensile strength in excess of 237,000 psi (1640 MPa). Supplied with RCM assembly lubricant. Vehicle fitment needs confirmation.

This 11mm performance head stud kit from RCM replaces the standard cylinder head bolts on Subaru EJ-series engines. Made from S99 steel with a manufacturer-stated minimum yield strength of 1080 MPa, supplied with ARP nuts, washers and RCM assembly lubricant.

Modified head dowels designed for use with 14mm head stud kits (reference RCM2902 and RCM593). Precision-cut and opened to fit over the larger 14mm stud shank. Supplied as a set of 4.

These billet aluminium half moon seals (also called cylinder head plugs) replace the OE plastic seals on Subaru EJ-series engines, which can harden and leak over time. Sealed using SGA35 liquid gasket. A complete engine requires 4 seals; sold as x1 or x4.

This blanking plate kit from RCM fits applications where the standard oil filler neck is no longer used, such as dry-sump conversions using an external oil tank. Available for V1-V4 and V5+ EJ-series engines.

This service refinishes Subaru rocker covers in STI-style crinkle paint, available in Red or Black. Covers are cleaned and stripped before recoating; customers must send in their own rocker covers to proceed.

This Superstud head stud kit from RCM (14mm/14mm) uses a larger 9/16″ diameter stud made from aircraft-grade S99 steel for Subaru EJ-series engines. Supplied with 12x ARP 9/16″ 8740 chromoly nuts and washers and compatible with RCM head gaskets.

This Superstud head stud kit from RCM (14mm/12mm) is made from aircraft-grade S99 steel for Subaru EJ-series engines. Supplied with 12x ARP M12x1.25 8740 chromoly nuts and washers and compatible with RCM head gaskets.