IAG 550 Street Cylinder Heads Package - W25 Heads (No Cams & Lifters / No Chamber Mods) - 2008-2018 Subaru STI

STOCK REPLACEMENT HEADS FOR BEGINNER PERFORMANCE

The IAG 550 Cylinder Heads are engineered to serve as a straightforward alternative to stock OEM heads. Whether your engine requires cylinder head replacement due to a major failure or you're starting from scratch without OEM heads, the IAG 550 Cylinder Heads offer a practical solution. Designed to accommodate vehicles equipped with basic bolt-on upgrades, these heads are suitable for power outputs up to 550 BHP. Enhanced with upgraded GSC standard size valves, GSC Viton Valve Stem Seals, IAG Stage 1 Valve Springs with Titanium Retainers, and OEM Keepers, these heads ensure dependable performance and longevity. Optionally, GSC S1 Camshafts are available with OEM valve lifter buckets for added versatility. Additionally, for EJ20 heads, we provide an optional chamber modification service, enabling compatibility with EJ25 short blocks.

 

CRAFTED FROM BRAND-NEW COMPONENTS

The IAG 550 Cylinder Head Set is initiated with fresh OEM castings sourced directly from Subaru of America, ensuring precise compatibility by selecting the appropriate Year and Model of your vehicle for tailored fitment. Additionally, you have the choice to integrate our GSC camshaft package, comprising new GSC S1 Camshafts and OEM Lifter Buckets for valve adjustment.

Following a thorough visual inspection, the bare castings are securely positioned within our in-house Centroid 5-axis CNC Machine. Here, they undergo meticulous cam clearance machining to accommodate potential upgrades, allowing for larger lift and duration cam profiles. Subsequently, the heads are meticulously fitted into our Newen Valve Guide and Seat Machine for a comprehensive multi-angle valve job on all intake and exhaust seats, meticulously aligned with the flow characteristics of GSC's standard size 36mm Intake and 32mm Exhaust valves. Post this process, the heads' decks are meticulously resurfaced to a smooth, uniform finish using our TS-3000 BlockMate. After undergoing ultrasonic cleaning to eliminate any debris and machining residues, the heads are meticulously reassembled, incorporating GSC Stainless Intake and Exhaust Valves, GSC Viton stem seals, IAG-Stage 1 Valve Springs with Titanium Retainers, and OEM Valve Keepers.

 

IAG 550 Street Cylinder Head Package Includes:

• (x2) Brand New Subaru OEM WRX or STI Cylinder Head Castings
• Multi-Angle Valve Job
• Machined Cam Lobe Clearance
• Resurface
• Ultrasonic Cleaning
• (x8) GSC 36mm (Standard) Intake Valves
• (x8) GSC 32mm (Standard) Exhaust Valves
• (x16) IAG Stage 1 Valve Springs & Titanium Retainers
• (x16) GSC Valve Stem Seals

 

Note: This Package does NOT include GSC Camshafts, Lifters, and Chamber Modification.