skip to Main Content

IAG Stage 4 Head – ‘D’ Casting 2006-2014 WRX | 06-10 FXT | 07-09 LGT

$3,999.99

IAG Stage 4 Head – ‘D’ Casting 2006-2014 WRX | 06-10 FXT | 07-09 LGT

  • Weight: 0 lb
  • Dimensions: N/A
  • Installation Difficulty:
SKU: IAG-ENG-3040D Categories: , ,

Description

IAG’s Stage 4 Cylinder Head Package utilizes a CNC porting program for the D25 heads that was developed over the past five years and tested on the most successful high-horsepower Subaru’s. The ported head package starts with brand new D25 WRX / Forester XT / Legacy GT OEM head castings directly from Subaru of America. The bare castings are visually inspected then fixtured into our in-house Centroid 5-axis CNC Machine one of the most advanced precision engine machining equipment in the world. The Centroid CNC ports the intake and hard to reach exhaust “dog-leg” port runner. The benefit of CNC porting is not only an efficient way of machining the heads it also offers consistent port results that are hard to achieve by hand. Once the Centroid completes the port process the heads undergo a cam clearance machining process that removes material from the lifter area where large duration cam profiles are known to contact the castings. Short after the heads are drilled to fit larger 1/2″ or 14mm head studs which are commonly used in high horsepower builds. Next the OEM guides are pressed out and replaced in favor of GSC Manganese-Bronze valve guides that are shaped to improve airflow. Once all the new intake and exhaust guides are in place they are diamond honed in our honing station. The heads are then fixtured in our Serdi 3.0 Valve Guide and Seat Machine to cut all intake and exhaust seat with multi-angle valve job that suits the flow characteristics of GSC’s 1mm valves. At this point the heads decks are resurfaced using our TS-3000 BlockMate that 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 Beehive Valve Springs and Retainers along with GSC Viton stem seals. Stage 4 Ported Head Package Includes: (x2) Brand New Subaru OEM D25 Cylinder Head Castings (x8) GSC 37mm ( 1mm) Intake Valves (x8) GSC 33mm ( 1mm) SuperAlloy Exhaust Valves (x16) GSC Beehive Springs & Retainers (x16) GSC Manganese-Bronze Valve Guides (x16) GSC Valve Stem Seals IAG Performance CNC Porting Multi-Angle Valve Job Drilling for compatibility with ? or 14mm Head Studs Cam Clearancing Resurface Ultrasonic Cleaning Recommendations / Warranty: Assembly and professional installation recommended. Workmanship/parts warranty will only be available for professionally installed cylinder heads.

Make Model Submodel Year
Subaru Forester XT 2006 - 2010
Subaru Legacy GT 2007 - 2009
Subaru WRX 2006 - 2014
Close search