GSC Power-Division 6.6mm stem Super Alloy +1mm Exhaust Valves for the 2JZ are for those running high horsepower, high EGT set ups that need a valve that will last in 2000°F conditions. The Super Alloy Exhaust valves have chrome polished stems to create a smooth, durable finish for added life and better lubricity, especially when paired with the GSC Manganese bronze valve guides. MUST BE PAIRED WITH GSC3113-12 VALVE GUIDES. Strength, heat resistance, and performance are engineered into every valve. Under head dish is maximized for weight savings while swirl polished and backcut heads promote better air flow without sacrificing durability. Head Diameter (mm) 6.6 99.20 30.00 GSC GSC Power-Division 6.6mm stem Super Alloy+1mm Exhaust Valve 2JZ-GE/GTE are for those running high horsepower, high EGT set ups that need a valve that will last in 2000°F conditions.