GSC Power-Division 30.5mm Exhaust Valves

The GSC Power-Division GSC2001-8 exhaust valves are engineered to be the best performing and longest-lasting valves available for the aftermarket, specifically designed for Mitsubishi 4G63 engines, including the 2003-2006 Evo. These valves feature a 30.5mm head diameter, a 6.6mm stem, and an OEM-equivalent overall length of 109.20mm. Constructed from modified 23-8N stainless steel, they offer high heat capacity while maintaining longevity. The exhaust valves are fully nitrated, which enhances valve life, improves sealing at the valve seat for better cylinder pressure, and reduces carbon buildup. These valves incorporate advanced design elements to optimize performance. The swirl-polished heads promote smoother airflow, while the back cut reduces valve weight, allowing for higher RPMs, increased boost pressure, and compatibility with more aggressive cam profiles without needing stiffer valve springs. The micro-polished stems minimize oil retention and drag for smoother operation. Additionally, the valve tips are hardened or feature a stelite wafer tip for extended life and reduced wear against the rocker or valve tappet. GSC has also adjusted the tip heights to minimize tipping during installation and ensure proper valvetrain geometry and lash settings.