Cosworth Subaru WRX STI EJ25 2.5L 2004-06 CNC Ported Big Valve Cylinder Head w/ KK 3920 CamsHAFTS

Cosworth CNC ported cylinder heads feature dyno tested and flow bench proven ports, engineered for maximum usable power. Each new cylinder head is ported on a 5 axis machine to ensure consistency and perfect port shape every time. Additionally, larger intake (+1mm) and exhaust valves (+1mm) are utilized to help increase flow.

Cosworth CNC ported Big Valve cylinder heads come complete with a performance valve job, hi rev (max 10,500rpm) valve springs with titanium retainers and are ready to install. Perfect for high performance applications.

These heads include our S2 version camshafts (KK3920- Japan/European) with the correct cam followers included. This is the perfect head/camshaft combination for serious performance and track day use.

Specification:

• CNC Ported/Machined finish port
• New Castings
• Hand blended finish work
• Intake 14.63% (average) 22% (max) increased flow
• Exhaust 30.56%(average) 41% (max) increased flow
• 4-angle Inlet Valve job
• 3-angle & radius Exhaust Valve job
• Valves are lapped
  
• Back-Cut Inlet Valves
• Heads are Ultra Sonic cleaned prior to assembly
• Heads are Serialized and sport a machined Cosworth logo
• +1mm Stainless Steel Intake Valves (1800 degrees max.)
• +1mm Inconel Exhaust Valves (2400 degrees max.)
• Performance Valve Springs
• Titanium Retainers
• Hardened Steel Spring Platforms
• In stock- ready to ship
• Knife edged ports
• Includes S2 Camshafts and cam followers installed