GSC Power Division 4041-16 Chromoly Spring Seats +.035 for Mitsubishi 4G63 Evo

Vehicle Fitment

• 1990-1999 Mitsubishi Eclipse GST / GSX (4G63T Turbo, FWD/AWD)
• 1990-1998 Eagle Talon TSi (4G63T Turbo, FWD/AWD)
• 1990-1994 Plymouth Laser RS Turbo (4G63T, FWD/AWD)
• 1991-1992 Mitsubishi Galant VR4 (4G63T, AWD)
• 1992-1999 Mitsubishi Lancer Evolution I-V (4G63T, AWD)
• 1999-2001 Mitsubishi Lancer Evolution VI (4G63T, AWD)
• 2001-2006 Mitsubishi Lancer Evolution VII-IX (4G63T, AWD)

Fitment Notes

• Designed exclusively for the 4G63T DOHC turbocharged cylinder head. Does not fit the 4G63 naturally aspirated variant.
• These seats are +0.035" thicker than OEM, which raises spring seat pressure without shimming - intended for high-performance and race builds requiring elevated seat pressure.
• For OEM-replacement thickness (no pressure change), see the GSC OEM-replacement spring seat set instead.
• Compatible with all GSC 4G63 valve spring kits including the GSC5041 Beehive kit, GSC5058 Race Beehive kit, and GSC5097 Race Conical kit. Also included as a bundled component in the GSC5097 and GSC5058 kits.

Features

• CNC-turned from Chromoly steel for superior strength and dimensional precision versus OEM stamped seats.
• Built 0.035" thicker than OEM, delivering increased spring seat pressure without shims or the risk of incorrect shim stacking.
• Eliminates reliance on multiple shims, simplifying installation and reducing the chance of valvetrain geometry errors.
• Designed for 4G63T builds pushing extreme cam lift, high boost, and elevated RPM levels.
• Compatible with OEM-style valve spring keepers or GSC1003 aftermarket keeper kit.
• Set of 16 covers all intake and exhaust positions in the 4G63T cylinder head.
• Consistent CNC tolerances ensure even spring seat pressure across all 16 valves.
• Pairs directly with all GSC 4G63 beehive and conical race spring kits.

Specifications

• Material: Chromoly Steel (CNC-turned)
• Additional Thickness vs. OEM: +0.035"
• Application: Mitsubishi 4G63T DOHC Turbo Cylinder Head
• Quantity: 16 (covers all intake and exhaust positions)
• Compatible Keeper: OEM-style or GSC1003

Included Components

• 16x GSC Chromoly Valve Spring Seats (+0.035" over OEM thickness)

Product Description

The GSC Power Division 4041-16 is a set of sixteen CNC-turned Chromoly valve spring seats engineered for the Mitsubishi 4G63T DOHC turbocharged engine. At +0.035" thicker than the OEM part, these seats raise spring seat pressure directly without the need for additional shims - a significant advantage on extreme builds where incorrect shim stacking can cause inconsistent seat pressures across the head or valvetrain geometry errors.

These seats are purpose-built for 4G63T builds operating at the absolute limit - high cam lift, elevated boost, and aggressive RPM targets where OEM seats and shimming setups simply aren't reliable enough. They are included as standard components in GSC's race-level spring kits (5058 and 5097) and are also available separately for builders who want the added seat height without a full spring kit change. Compatible with all GSC 4G63 beehive and conical spring sets, and work with both OEM-style keepers and the GSC1003 aftermarket keeper kit.