RCM 14/12mm Superstud Cylinder Head Stud Kit

Ease of Fitment Guide: Beginner

List Price (exc VAT): £469.99 Sale price Your Price: £563.99
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The latest evolution of our proven and hugely successful 14/12mm RCM Head Stud Kit designed for the ultimate in engine performance and reliability! Introducing the new RCM 14mm Superstud Head Stud Kit.

Our engineers have taken the ultimate EJ series head stud solution to the next level by incorporating some new features into the RCM 14mm Superstud kit to improve performance and ease of installation for your EJ engine.

• Larger size stud (still compatible with RCM Head Gaskets)
• Supplied with x12 ARP M12 x1.25 8740 Chromoly 12pt nut
• Supplied with x12 ARP 12mm 8740 Chromoly washer
• Incorporating hex in stud end for super easy install

It is essential engines modified to 500+bhp have the most reliable system for clamping the cylinder heads onto the block assembly to avoid the heads lifting under load at high levels of boost pressure. The RCM 14mm /12mm Superstud Head Stud kit provides this peace of mind!

Now used in many of the fastest and most powerful Imprezas across the globe the RCM 14mm /12mm Superstud Head Stud Kit is quite simply the foundation on which all our high bhp engine conversions (including Gobstopper and Gobstopper 2) race engines are built around. Replacing the conventional 11mm Subaru cylinder head bolts with a series of 14mm precisely manufactured super high tensile, aircraft grade S99 steel stud and nut system offers many advantages when building your engine. With a tensile strength much higher than that of the OE bolts and the increased stability provided by the RCM studs larger diameter when further combined with the more uniform clamping force provided by the stud and nut arrangement it is clear why so many championship winning engines run these kits!

All kits are supplied with RCM's own assembly lube, which utilizes Graphite DJ technology, ensuring you are able to install to the correct torque figures accurately.

• Cylinder head studs manufactured using "Aircraft Grade S99 High Tensile Steel" to WRC specification.
• Precision rolled threads.
• Cylinder head stud thread pitch (Block End): M14X2.
• Cylinder head stud thread pitch (Cylinder Head end): M12 x 1.25.
• Cylinder head stud length: 197mm.


• Supplied in the kit are:


• x12 RCM 14mm head studs.
• x12 ARP M12 x 1.25 8740 Chromoly 12pt nut
• x12 ARP 12mm 8740 Chromoly washer
• 1x Sachet of assembly lube and fitting guide for a comprehensive install.

• To allow fitting of the RCM 14/12mm Head stud kit your engine block must be re engineered to accept the larger studs used in this kit. RCM can carry this work out for you at  additional cost (see part number RCM237 or contact us for more details).

Non RCM manufactured head gaskets used alongside this kit will require slight modification using our tapered reamer tool (See part number RCM910).


• Huge increase in tensile strength and yield when compared with the OE head bolts.

• Massively increased clamping load for big bhp applications.

• Eliminates cylinder head lift at high levels of boost.

• Supplied with ARP high tensile nuts, washers, RCM assembly lube and installation guide.

• As used in RCM Gobstopper I + II Time Attack race cars.

Suitable for all EJ20/22/25 series block cases.

If you are unsure of fitment then please check your engine code or contact our sales department.

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