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 and are ready to install. Perfect for big turbo applications. Subaru heads are priced for the pair. A flow chart for the head is available by downloading the technical document on the left.

Specification
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