Cosworth CNC Ported Big Valve Cylinder Head Subaru WRX STI 2.5L EJ25 04-06

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.

Specifications:
* 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
* Knife edged ports

KK3670 is designed to fit 2004-2006 WRX STI EJ25 (2.5L) North American spec vehicles.