Engineered to perform under the most extreme of conditions our cylinder head gaskets are rated for use up to and over 600BHP. Unlike most conventional cylinder head gaskets, our gaskets use what is most commonly known as a Ðfolded stopper levelÓ. This revolutionary design dramatically reduces the chances of any pressure leakage from the cylinders. An increased thickness in the gasket is introduced around vital sealing areas and the design of this extra layer forms a much stronger barrier to prevent gasses / pressure / water and oil escaping from its designated area. The layer acts as a very reliable defence and is highly recommended for any Subaru, specifically those running above the standard factory torque / horsepower figures. In conjunction with this new technology our gaskets also feature a unique nitrile rubber coating. This coating is designed to act as a cushion in which to fill / take up any areas of imperfection found in either the cylinder head or block faces, to ensure you have the very best combustion chamber armour! Finally our cylinder head gaskets are all stamped from dies as appose to laser cut. With die stamping you can process a large amount of material at once which means that variations in the quality of each individual gasket is far less compared to laser cutting (in which each gasket section is cut separately to one another). With Die Cutting the finished edges are also far superior, leaving a much smoother, neater edge to the gasket as appose to laser cut steel which leaves a sharper edge behind. For the ultimate seal all our gaskets are manufactured and designed to accept the larger 12mm and 14mm cylinder head studs also available from our online store. The standard cylinder head bolt (the component that joins the cylinder head to the block and offers force to seal your cylinder head gasket in place) is 11mm thick and uses a relatively fine thread. It is important to remember this bolt was developed for use on a mainstream engine producing no more than 320Bhp, Subaru did not manufacture this bolt for use with anything above this power and as such it is important to consider stronger and more suitable replacements. Here at RCM we manufacture both a 12mm and 14mm replacement head stud and nut kits. The studs are naturally stronger due to their extra thickness and superior material quality but they also benefit from a much coarser rolled thread (meaning you can tighten them far more than the standard bolt which in turn will offer a much higher clamping load between both the cylinder head and block faces where you head gasket is situated.) Reliability is key to any engine rebuild, whether done for higher horsepower applications or just a simple repair / refresh its important to choose your components wisely so that you don?t end up repeating the process later down the line.