IAG Stage 3 Pocket Ported Heads Pkg Stage 3 Pocket Ported Heads w/ +1mm GSC Valves & GSC S2 Cams 25 Casting

Subaru: Legacy 05 - 06, Subaru: Impreza 04 - 07, Subaru: Forester 04 - 05

• Recommendations / Warranty: For use with stock cams or mild duration cams Assembly and professional installation recommended. Workmanship/parts warranty will only be available for professionally installed cylinder heads.
• Stage 3 Ported Head Package Includes: (x2) Brand New Subaru OEM V25 Cylinder Head Castings, (x8) GSC 37mm (+1mm) Intake Valves, (x8) GSC 33mm (+1mm) SuperAlloy Exhaust Valves, (x16) GSC Single Valve Springs & Titanium Retainers, (x16) OEM Valve Guides, (x16) GSC Valve Stem Seals, (x1) GSC S2 Billet Camshaft Set, (x16) OEM valve lifters, IAG Performance CNC Pocket Porting, Multi-Angle Valve Job, Machined Cam Lobe Clearance, Ultrasonic Cleaning

IAG 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 V25 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. The Centroid CNC ports the intake and exhaust runners under the valves and blends them to the valve seat. Once the Centroid completes the port process the heads receive our combustion chamber modification in which the shapes of the chamber are machined to reduce compression and improve the burn path. The heads then 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. Next, the heads are 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 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 reassembled using GSC Billet S2 camshafts intended for vehicles making 500+ wheel horsepower. The cams are matched to GSC Single Valve Springs and Titanium Retainers along with GSC Viton stem seals.