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SKU: 3025.001-1
GSC Subaru 2002-2021 WRX STI EJ205 EJ207 EJ257 EJ257B Exhaust Valve Guide Stopper Style +.001in OD - Single
Upgrade your Subaru EJ engine with the GSC Power-Division exhaust valve guide in stopper style and +0.001in OD. This single guide fits EJ205 EJ207 EJ257 and EJ257B cylinder heads found in WRX and STI models from 2002-2021. It delivers reliable sealing and durability for turbocharged performance applications.
Key Features
- Stopper Style Design: Built-in lip seats guide at exact height to avoid over-insertion and maintain valve stem alignment
- +0.001in OD Sizing: Oversized outer diameter fits guide bores with minor wear for restored precision without full reaming
- Manganese Bronze Material: High-strength alloy resists heat and wear in exhaust ports under boost pressure
- Exhaust-Specific Engineering: Optimized shape and tolerances improve sealing and flow for better power output
- Precision CNC Machining: Ensures micron-level accuracy for drop-in compatibility and long-term valvetrain stability
Product Notes
- Sold as single guide, order quantity needed for full cylinder head rebuild
- Inspect cylinder head guide bores for wear before installation
- Securely packaged in protective tube for damage-free delivery
Installation Notes
- Professional installation recommended.
- Hone guide bores to 0.376in diameter to match +0.001in OD
- Compatible with stock or aftermarket valves, lash caps, and retainers
This Part Fits
| Year | Make | Model | Submodel |
|---|---|---|---|
| 2002-2007 | Subaru | Impreza | WRX |
| 2004-2021 | Subaru | Impreza WRX | STI |
| 2001-2007 | Subaru | Impreza WRX STI | JDM |
| 2004-2009 | Subaru | Legacy | GT Spec B |
| 2008-2014 | Subaru | Impreza WRX | Hatchback STI |
| 2015-2021 | Subaru | WRX STI | Sedan |
Why Choose GSC Power-Division?
- Proven in professional racing Subaru builds worldwide
- High-volume production with strict quality controls
- Engineered for extreme boost and RPM demands
Frequently Asked Questions
-
Q: Will this fit 2004-2021 USDM STI EJ257 heads?
A: Yes, direct fit for EJ257 and EJ257B exhaust positions in STI models from 2004-2021 -
Q: What material is used for the guide?
A: Manganese bronze for superior heat resistance and low friction on exhaust valve stems -
Q: Is machining required for installation?
A: Bore honing to 0.376in recommended for optimal press fit, professional shop advised
Shipping & Handling
- Method: UPS Ground or USPS Priority
- Availability: In stock - ships same or next business day
- Packaging: Protective plastic tube, 4in x 2in x 1in box
- Weight: 0.1 lbs
GSC Power Division
GSC Power Division is a manufacturer of precision-engineered camshafts, valve springs, and valvetrain components designed for high-performance and competition engines across domestic, import, and diesel platforms. Founded by engineers with deep roots in motorsport, GSC Power Division components are machined to exacting tolerances and heat-treated to survive the demands of forced induction and high-rpm applications that destroy stock valvetrain parts. The brand is particularly well-known in the Mitsubishi Evo, Subaru STI, Nissan RB, and Toyota 2JZ communities where aggressive camshaft profiles are essential for extracting maximum power from turbocharged four-cylinder and six-cylinder engines. Whether building for drag racing, road course competition, or a high-powered street car, GSC Power Division camshafts and valve springs are a proven upgrade path. Popular Upgrades GSC Power Division S1, S2, and S3 camshafts are the most popular selections, with each profile offering progressivel...
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