The Cosworth CNC Ported Cylinder Head has been designed
to take the 4G63 to the next level. This cylinder head is for those
with the Mivec option, and Cosworth starts out this arduous process with
a brand new head.
Each Cylinder head has been has been ported by a 5 axis machine which promotes consistency and superior flow, as well as a perfect port shape every time. Larger stainless steel intake and inconel exhaust valves have been installed, increasing the valve size to +1MM larger then stock to increase air flow through the head. The heads are a dreastic improvement over the factory flow characteristics and provide quicker response and spool up to help increase performance through the entire RPM range.
The Cosworth CNC ported big valve cylinder heads also come pre-installed with the Cosworth Ultra High RPM series of valve springs and retainers, which feature a 10,500RPM rev limit!