Bourne HPP K-Series High Performance Exhaust Valve Set Maximize the durability and flow of your cylinder head with this premium exhaust valve set, developed by Bourne HPP. Designed as a superior replacement for standard components, these valves are engineered to withstand the extreme thermal stress of high-output K20 and K24 engines. Manufactured from high-grade EN52 steel, these valves are specifically formulated to resist the immense heat generated during the exhaust cycle. The addition of a Pulse Plasma Nitrided coating significantly increases surface hardness and wear resistance, while the super polished finish ensures smoother airflow and helps prevent carbon buildup, making them an ideal upgrade for both turbocharged and high-compression naturally aspirated applications. Key Specifications Fitment: K20 / K24 (Exhaust Side) Material: EN52 Steel Finish: Super Polished Coating: Pulse Plasma Nitrided Dish Capacity: 0.31cc Status: Performance upgrade Performance Pedigree These valves have been selected for their ability to perform under the harshest conditions. The EN52 material provides exceptional thermal stability, preventing warping or failure under high exhaust gas temperatures. The advanced Pulse Plasma Nitriding process reduces friction and improves scuff resistance, ensuring long-term reliability in championship-winning engines where consistency is key. Kit Contents 8x Bourne HPP Exhaust Valves Installation Note: Please note that these are sold in a pack of 8, which covers the exhaust side of a standard K-Series cylinder head. When installing, we recommend checking valve-to-guide clearances and ensuring a proper valve seat seal. We recommend professional installation and machining if required.