GSC Power-Division Stainless Steel Exhaust Valves +1 - 2002-2014 WRX, 2004-2021 STI

GSC set out to create the best performance, longest lasting Subaru intake valves available to the aftermarket. Using advanced 3D design and simulation programs GSC created a stronger and higher flowing valve head design. GSC flow tests prototype valve heads to specific applications, making sure they have the highest flowing valve head available on the market today. The materials used by GSC have less valve distortion at the face than any of the tested designs. Less distortion allows better sealing under extreme conditions and more consistent performance thru the life of the valve.

Features:

• 33mm +1 Size Exhaust Valves
• Swirl polished heads for smoother air flow over the valve
• Back cut to reduce valve weight for higher rpm, higher boost pressure and allow for more aggressive cam profiles without increasing valve spring seat pressures.
• Valve stems are micropolished to allow for less oil retention on the stem which creates less drag on the stem to guide for a smoother motion.
• Intake valves are a modified 21-4n stainless steel
• Valve tips are either hardened or have a stelite wafer tip fused so that the tip is within 5 Rockwell C of the rocker or valve tappet for extended life and less wear
• Valve tip lengths. GSC took extra time to adjust tip heights on the applications to require less tipping of the valve to maintain proper tip height for proper valve train geometry and to cut down on install times when setting valve lash.
• GSC also adjusted the Keeper grove to properly balance intake spring pressures to reduce the use of valve spring shims and maximize performance from spring and retainer kits.
• Valves will work with an oem keeper/lock or when available, GSC upgrade keeper/lock.
• *It's not mandatory but it is suggested that any valve lock not be reused on performance applications do to material grooving.