IAG Stage 1 Cylinder Head Package For 02-05 WRX 2.0L S20 Castings (Cams / Lifter Buckets Sold Separately).

IAG Stage 1 Cylinder Head Package: IAG's Stage 1 cylinder heads are intended for those looking for a cost-effective OEM+ replacement. Each package starts with brand new S20 WRX OEM head castings, directly from Subaru of America. The bare castings are visually inspected and then fixtured into our in-house Centroid 5-axis CNC Machine. This is one of the most advanced pieces of precision engine machining equipment in the world. In the Centroid, the heads undergo a cam clearance machining process which removes material from the lifter area where larger lift and duration cam profiles are known to contact the castings. Then the heads are then fixtured in our Serdi 3.0 Valve Guide and Seat Machine to cut all intake and exhaust seats with a multi-angle valve job that suits the flow characteristics of GSC's standard size 36mm Intake and 32mm Exhaust valves. At this point, the heads' decks are resurfaced using our TS-3000 BlockMate, which cuts the aluminum to a smooth, even finish. Next, the heads are ultrasonically cleaned to remove debris and oils from the machining process. Finally, the heads are assembled using GSC Single Valve Springs and Titanium Retainers along with GSC Viton stem seals.

• New Head Castings, GSC Valves, GSC Springs and Retainers