BLOX Racing high compression, stardard size valves are forged from EV8 stainless steel. Each valve then undergoes a heat treatment process to increase strength then coated using black nitride to provide superior wear resistance and minimize power-robbing friction.BLOX Racing valves are specially designed to increase intake and exhaust airflow through the cylinder heard. BLOX Racing valves increase compression by approximately 0.3 points.For best results, use with BLOX Racing valve springs and Ti retainers.NoteSet includes 8x intake valves and 8x exhaust valves