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IAG Performance Stage 5 Cylinder Head Package w/ Ferrea +1mm Valves and GSC S3 Cams 2007 STI V25 Heads

Original price $7,479.99 - Original price $7,479.99
Original price
$7,479.99 - $7,479.99
Current price $7,479.99

IAG's Stage 5 Cylinder Head Package utilizes a CNC porting program for the Subaru WRX STI 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 WRX STI 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 seats with a multi-angle valve job that suits the flow characteristics of Ferrea +1mm valves. At this point, the heads decks are resurfaced using our TS-3000 BlockMate that cuts the aluminum to a smooth even finish. After resurfacing, the heads are ultrasonically cleaned to remove debris and oils from the machining process. The heads are then reassembled using GSC Billet S3 camshafts designed for drag racing applications intending to make 750-1000 wheel horsepower. During the final assembly, the cams are matched to Ferrea Dual Valve Springs and Titanium Retainers along with Ferrea valve stem seals then bench-lashed to a tolerance that is close to final specifications.

Stage 5 Ported Head Package Includes:

  • (x2) Brand New Subaru OEM Cylinder Head Castings
  • (x8) Ferrea 37mm (+1mm) Comp Plus Intake Valves
  • (x8) Ferrea 33mm (+1mm) Comp Plus Exhaust Valves
  • (x16) Ferrea Dual Valve Springs & Titanium Retainers
  • (x16) GSC Manganese Bronze Valve Guides
  • (x8) Ferrea 6mm Intake Valve Stem Seals
  • (x8) Ferrea 6mm Exhaust Valve Stem Seals
  • (x16) OEM Lifter Buckets
  • GSC S3 Billet Camshafts
  • IAG Performance CNC Porting
  • Multi-Angle Valve Job
  • Drilling for compatibility with ½" or 14mm Head Studs
  • Machined Cam Lone Clearance
  • Resurface
  • Ultrasonic Cleaning
  • Bench Lashed

GSC D25 & V25 Camshaft Specs: (06-14 WRX / 07 STI, 06-13 FXT / 07-09 LGT)
S3 Billet Cam is intended for 750-1000WHP

7025S3 ADV Duration Duration @ 0.040" Peak Lift Center Line
Intake 280° 240° 11.55mm 130°
Exhaust 280° 241° 11.60mm 115°

Recommendations / Warranty:

  • Final lash will need to be set upon the long blocks assembly.
  • Assembly and professional installation recommended.
  • Workmanship/parts warranty will only be available for professionally installed cylinder heads.

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