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IAG Stage 4 Cylinder Head Package N Castings  - Subaru STI 2018-2021

IAG Stage 4 Cylinder Head Package N Castings

Subaru STI 2018-2021

IAG Stage 4 Cylinder Head Package N Castings  - Subaru STI 2018-2021
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Part # IAG-ENG-3040N
$4,199.99

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 4 CNC Ported 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 also utilize a CNC porting program for the WRX STI heads that has been under development for the last 5 years, and they have been tested on the most successful high-horsepower Subarus. 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 GSC Beehive Valve Springs and Retainers along with the GSC Viton Stem Seals. 

 

 

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 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
  • The heads are then drilled to fit 14mm or 1/2" head studs which are commonly used in high-horsepower builds
  • OEM guides are then pressed out in favor of GSC Manganese-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 using GSC Beehive Valve Springs and Viton Valve Stem Seals
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    CONTENTS INCLUDE:

  • (2) Brand new Subaru OEM cylinder head castings
  • (8) GSC 37mm (+1mm) Intake Valves
  • (8) GSC 33mm (+1mm) SuperAlloy Exhaust Valves
  • (16) GSC BeeHive Springs And Retainers
  • (16) GSC Manganese-Bronze Valve Guides
  • (16) GSC Valve Stem Seals
  • IAG Performance CNC porting
  • Multi-angle valve job
  • Drilling for compatibility with 14mm or 1/2" head studs
  • Machined cam lobe clearance
  • Resurfacing
  • Ultrasonic cleaning
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    NOTES:

  • The cams and lifters are sold separately
  • Professional installation required
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    Specifications

    Brand: IAG Performance
    Head Alteration Required: No
    Includes Camshafts: No
    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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