Cosworth CNC ported cylinder heads feature dyno tested and flow bench proven ports, engineered for maximum real world 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.

Cosworth has been engineering camshafts for nearly 50 years. That coupled with years of innovative multi valve cylinder head design ensures our camshaft designs or the most efficient in providing maximum usable power across the widest power band. Each cam is ground from a new chill cast billet and finished using the same procedures we use in our extreme level race engines. Cosworth camshafts are the perfect compliment to our CNC Ported Big Valve Cylinder heads. Our Subaru EJ25 cams are profiled to increase boost response thereby increasing engine torque and power and are fully compatible with the Subaru STI AVCS.

Specification
Heads:
CNC Ported/machine finished ports - New OE Castings
Hand blended finish work
Intake 22% Increased Flow (max)
Exhaust 41% Increased Flow (max)
4-angle Inlet Valve job
3-angle & radiused 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 Edge port divider

Cams:
Ground from new chill cast billets
North American Spec AVCS compatible