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IAG Stage 5 Cylinder Head Package N Castings w/ GSC S3 Cams & New Lifter Buckets - Subaru STI 2018-2021

IAG Stage 5 Cylinder Head Package N Castings w/ GSC S3 Cams & New Lifter Buckets

Subaru STI 2018-2021

IAG Stage 5 Cylinder Head Package N Castings w/ GSC S3 Cams & New Lifter Buckets - Subaru STI 2018-2021
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Part # IAG-ENG-3055NS3
$6,799.99

Product will ship from manufacturer, average time to ship: 56 business days
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Features & Product Details

RallySport Direct now carries highly sought-after high-performance upgrades and accessories brought to you by IAG Performance. 

 

These are the IAG Performance Stage 5 Cylinder Heads. These heads have been engineered with precision utilizing the best combination of components to sustain high horsepower and high boost builds. These heads start out as brand new OEM head castings directly from Subaru Of America, where the bare castings are inspected before fixtured onto IAG's in-house Centroid 5-axis CNC machine. This machine is considered to be one of the most advanced precision engine machining tools available in the world. 

 

The Centroid CNC ports the intake and hard to reach exhaust "dog-leg" port runner to achieve consistent port results that are very difficult to achieve by hand. Once the Centroid completes the porting process the heads are then cleared for the cams, and it removes any material from the lifter area where large duration cam profiles are known to contact the castings. Shortly after, the heads are removed and drilled to fit larger 1/2" or 14mm head studs which are commonly used in high-horsepower builds. Then the OEM guides are pressed out in favor of GSC Manganese-Bronze valve guides that are shaped to improve the airflow. The heads are then reassembled using Ferrea Dual Valve Springs and Titanium Retainers along with Ferrea Intake and Exhaust Valve Stem Seals. Additionally, this head package will come equipped with a set of GSC S3 camshafts.

 

 

FEATURES:

  • The heads start out as brand new castings from Subaru Of America
  • Heads are then machined in-house at IAG utilizing a Centroid 5-axis CNC machine
  • The Centroid CNC ports the intake and hard to reach "dog leg" exhaust ports
  •  The Centroid CNC provides consistent porting results 
  • The heads are then drilled to fit 14mm or 1/2" head studs which are commonly used in high-horsepower builds
  • The heads will then undergo a cam clearance machining process
  • Material will be removed from the lifter area where larger duration cams are known to make contact with the castings
  • OEM guides are then pressed out in favor of Ferrea Copper-Bronze valve guides that are shaped to improve airflow
  • Once the guides are in place they are diamond-honed in IAG's honing station
  • The heads are then fixtured to IAG's Serdi 3.0 Valve Guide and Seat Machine to cut all the intake and exhaust seats
  • A multi-angle valve job is performed to suit the flow characteristics of the GSC +1mm valves
  • Heads are then resurfaced using IAG's TS-3000 Blockmate that cuts the aluminum to a smooth and even surface
  • The heads are then ultrasonically cleaned to remove debris and oil from the machining process
  • Reassembly then begins
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    CONTENTS INCLUDE:

  • (2) Brand new Subaru OEM WRX STI cylinder head castings
  • (8) Ferrea 37mm (+1mm) Comp Plus Intake Valves
  • (8) Ferrea 33mm (+1mm) Comp Plus Exhaust Valves
  • (16) Ferrea Dual Valve Springs, Locators, and Titanium Retainers
  • (16) Ferrea Copper-Bronze Valve Guides
  • (16) Ferrea 6mm Intake and Exhaust Valve Stem Seals
  • (16) OEM lifter buckets
  • GSC S3 billet camshafts
  • IAG Performance CNC porting
  • Multi-angle valve job
  • Drilling for compatibility with 14mm or 1/2" head studs
  • Cam lobe machine clearance
  • Resurfacing
  • Ultrasonic cleaning
  • Bench lashed
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    NOTE:

  • Professional installation required
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    Specifications

    Brand: IAG Performance
    Head Alteration Required: No
    Includes Camshafts: Yes
    Machining Required: No
    Material: Aluminum
    QTY: Package
    Springs Included: Yes
    Valves Included: Yes
    Mfgr. Warranty: 12 Months / 12k Miles
    Condition: New Product
    Return Policy:
    Standard

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