GSC Power Division 2001-8 Chrome Polished Exhaust Valves for 4G63T Evo 1-9/DSM

Vehicle Fitment

• 1992-2006 Mitsubishi Lancer Evolution I-IX (4G63T, AWD)
• 1990-1999 Mitsubishi Eclipse GST / GSX (4G63T, FWD/AWD)
• 1990-1998 Eagle Talon TSi (4G63T, FWD/AWD)
• 1990-1994 Plymouth Laser RS Turbo (4G63T, FWD/AWD)
• 1991-1992 Mitsubishi Galant VR-4 (4G63T, AWD)

Fitment Notes

• Fits all Mitsubishi 4G63T turbocharged applications including DSM 1G (1990-1994) and 2G (1995-1999) platforms, and Evo I through IX (1992-2006)
• Does not fit the Evo X (4B11T engine) - see GSC part numbers in the 4B11T lineup for that application
• Does not fit the naturally aspirated 4G63 (non-turbo) found in some Eclipse base trims
• Standard (STD) 30.5mm head diameter - confirm existing valve seat diameter before installation; use oversized valves if seats have been cut

Features

• Modified 23-8N stainless steel alloy construction provides superior high-heat capacity and oxidation resistance for turbocharged exhaust applications
• Chrome polished valve stems reduce oil retention and minimize drag against the valve guide for smoother, more consistent motion throughout the RPM range
• Swirl polished valve heads promote improved airflow over the valve face, boosting combustion efficiency and overall engine output
• Back-cut valve heads reduce valve weight, enabling higher RPM capability, higher boost pressure tolerance, and compatibility with more aggressive cam profiles without raising spring seat pressures
• Maximized under-head dish for additional weight reduction while maintaining structural integrity under high-EGT conditions
• Precision-adjusted valve tip lengths minimize the need for tipping at installation, maintaining proper valve train geometry and reducing setup time when setting valve lash
• Engineered keeper groove geometry balances intake and exhaust spring pressures, reducing reliance on valve spring shims and optimizing spring and retainer performance
• Valve faces exhibit less distortion under extreme conditions versus tested OEM and competing aftermarket designs, enabling superior sealing and consistent performance over the life of the valve
• Designed, machined, and tested in-house on dedicated CNC machining centers to tight tolerances using advanced 3D FEA and flow simulation software
• Flow tested in specific engine applications to confirm the highest flowing valve head design available in the sport compact aftermarket

Specifications

• Position: Exhaust (set of 8 - one per cylinder, full engine set)
• Valve Head Diameter: 30.5mm (STD / Standard Size)
• Valve Stem Diameter: 6.6mm
• Overall Valve Length: 109.20mm
• Material: Modified 23-8N stainless steel
• Stem Finish: Chrome polished
• Head Finish: Swirl polished with back cut
• Application Engine: Mitsubishi 4G63T (2.0L DOHC Turbocharged I4)
• Quantity per Set: 8

Included Components

• 8x GSC Power Division Chrome Polished STD Exhaust Valves (30.5mm head, 6.6mm stem, 109.20mm length)

Product Description

The GSC Power Division 2001-8 is a set of eight standard-size (30.5mm) chrome polished exhaust valves engineered specifically for the Mitsubishi 4G63T turbocharged engine found in the Lancer Evolution I-IX and all DSM platforms including the Eclipse GST/GSX, Eagle Talon TSi, Plymouth Laser RS Turbo, and Galant VR-4. Constructed from a modified 23-8N stainless steel alloy, these valves are purpose-built to withstand the elevated exhaust gas temperatures (EGTs) generated in high-boost, high-horsepower 4G63T builds, where OEM valves are prone to distortion, seat leakage, and premature wear under sustained stress.

Every design decision in the GSC 2001-8 is targeted at performance and longevity. The chrome polished stems reduce oil accumulation and guide drag for smoother operation, the swirl polished and back-cut heads improve airflow and reduce valve mass for higher RPM and boost compatibility, and the precision-engineered keeper groove geometry helps balance spring pressures between intake and exhaust sides - minimizing shim use and ensuring optimal valvetrain geometry right out of the box. GSC further refined valve tip lengths to reduce the amount of tipping required during installation, making this a more installer-friendly option compared to generic aftermarket alternatives.

These valves are a direct replacement for the stock exhaust valves in any 4G63T head and are sold as a complete engine set of 8. They are especially well-suited for builds running aggressive camshafts, upgraded valve springs, or forced induction setups where heat and pressure cycles demand more from the valvetrain than OEM components can reliably provide. For maximum performance and longevity, GSC recommends pairing these valves with their Manganese Bronze valve guides and Viton valve stem seals. Standard 30.5mm head diameter - verify that cylinder head valve seats are in good condition and have not been previously cut oversized before ordering the STD size.