Cosworth 20004544 CNC Ported Big Valve Cylinder Head 08-09 Subaru WRX STI EJ25 2.5L

Cosworth 20004544 CNC Ported Big Valve Cylinder Head 08-09 Subaru WRX STI EJ25 2.5L

Cosworth Big Valve Cylinder heads for the Dual AVCS 2008 STI EJ257B engine. Machine Ported for maximum accuracy and performance, complete with larger (+1mm) valves and dual valve springs for maximum flow. Cosworth Big Valve Cylinder heads are the key to high power and unlocking the performance potential in your Subaru engine.

Specifications:

• CNC Ported/Machined finish port
• New Castings
• Hand blended finish work
• Intake 13.63% (average) 19.38% (max) increased flow over stock 05 casting
• Exhaust 31.44%(average) 37.78% (max) increased flow over stock 05 casting
• 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
• With dual AVCS