Maximum performance, bracket racing, heads up and super classes. 7,500 RPM, 540+ cubic inches, great head for maximum effort, comp or bracket cars. The PRO1 24 Deg 365cc CNC is for uncompromising performance and racing applications which favor high RPM power over low end flexibility. Best for big cubic inch, high RPM use. Every intake port, exhaust runner, valve bowl, and every combustion chamber is 100% CNC machined on special dedicated PRO1 castings. Our 5-axis, computer controlled machining centers produce compound curves and complex shapes that no human could duplicate with a hand grinder. Assemblies include Stainless Steel valves, premium springs, locks, retainers, guide plates and seals. Assemblies include Stainless Steel valves, premium springs, locks, retainers, guide plates and seals.