Honda S2000 Race Ported Cylinder Head F20C. Work carried out by BTCC Engineer Simon Erland with software calculations to maximise porting improvements. Inlet & Exhaust ports worked to maximise flow including the tough curve on the short side which must be correct to avoid the flow detaching; removing the guide and guide boss makes such a step change – because that messes up the flow as well as acts as a block. This head will flow substantially better than the cnc heads just because they leave the boss in and it has a disproportionate effect. Exhaust Studs Drilled & Tapped to M10 to avoid backing off in high performance high heat applications. EGR on exhaust ports tapped and blanked locked in place with high temp Titanium paste used; this was done to illuminate a flow restriction on cylinders keeping exhaust gas speed high on cylinder exit. Bronze Valve Guides fitted & cut flush with ports to prevent turbulance illiminating a major flow blocker; will require guide bores honing to valves used. Chambers have been worked with a approximate 3-4cc gain on stock; tungsten cutters used to unshroud the valves and remove all the hard machined edges up the side of the chamber and around the seat. This allows each valve to flow better & done without widening the whole chamber and requiring a deep skim to recover CR. A Light skim 2-3 Thou recommended to throughly clean head mating surface although around 10 thou would return head to original Compression Ratio based off of the chamber work. Valves for this head have been designed to further add to the gains made, please see our other listing.