Ferrea 6000 Series Exhaust Valve - Honda Prelude H22A1/A4 Stock Size - Set of 8 - F6023The 6000 Series Competition Valves are designed to provide excellent reliability in an environment of high spring pressures and roller cams, at a budget price. They have higher fatigue resistance and tensile strengths than our competitors best offerings. To manufacture the valves we use our exclusive two step slow forging process using EV8 stainless steel on both intake and exhaust valves. We provide a special heat treatment and stress relieving