Stage 3 Pocket Ported Heads w/CM/+1mm Valves S20 Casting(Cams/Lifters Sold Sep) 2018-subaru-wrx sti-type ra The copper exhaust nuts are

The copper exhaust nuts are designed to replace the OEM exhaust nuts at the Subaru manifold to cylinder head location

Chamber Modification

25mm on our in-house Sunnen SV-30 the most advanced automotive cylinder hone available

but allow you to upgrade to 90A or Solid bushings in the future

water pump

Stage 3 Pocket Ported Heads w/CM/+1mm Valves S20 Casting(Cams/Lifters Sold Sep) 2018-subaru-wrx sti-type ra The copper exhaust nuts areIAG Stage 3 Pocket Port Cylinder Head Package: The head package centers around our popular CNC pocket porting program which was developed over the last several years. Pocket porting removes excess OEM casting flash and the material underneath the valves. By smoothing and blending this area under the valve seat, significant flow capability can be achieved. The IAG Stage 2 pocket ported head package starts with brand new WRX STI OEM N25 head castings,