Since 1938, Kibblewhite has taken great pride in their ability to design innovative performance improvements for the valvetrain. This innovative ability has never been more apparent than with the development of the high-tech lightweight stainless steel conversion systems for the incredibly stressed and torturous environment in today's ultra high revving 4-stroke singles. The challenge to engineer valvetrain that would outperform O.E.M. systems that in some cases included titanium components was not an easy one. This task would require the concentrated efforts of every member of Kibblewhite's design team. It was apparent early on that a lightweight high flowing Kibblewhite stainless race valve was not going to be the complete answer for these engines. Working together as a team enabled Kibblewhite to evolve with a "unified system" approach. In fact, this innovative lightweight system would not only out-perform factory parts, but outlive them as well. Black Diamond™ Valves: All KPMI Black Diamond™ stainless steel valves are impregnated by a special German process to a depth of 0.002", with a surface build up of 0.0002". This "Black Diamond™" process improves wear properties, reduces friction, and provides resistance to corrosion and wear that is superior to chrome and nickel electrolysis plating. Each valve is designed using Finite Element Analysis software, and profiles are tested on Kibblewhite's computerized flow bench. Black Diamond™ Valves are light, strong, one-piece forgings with profiles that provide excellent flow characteristics and will outlast titanium valves. White Diamond® Valves: KPMI fully CNC machines their White Diamond® Valves from a one-piece forging of either EV8 Stainless Steel or Inconel-751. These materials have proven heat and corrosion resistance properties. Each valve is designed using Finite Element Analysis software, and profiles are tested on computerized flow bench. Strict attention is paid to the surface preparation of the valves, and the purity of the chrome is closely monitored. A 360-degree anode is used to produce the highest possible grade of hard chrome finish. White Diamond® Valves are light, strong, one-piece forgings with profiles that provide excellent flow characteristics. Inconel® is classified as a "Super Alloy," meaning that it is designed to survive under the most extreme temperatures and pressures, where other valves will begin to burn, corrode, or completely fail. This is the material of choice for high output engines running turbos, superchargers, nitromethane, or nitrous. Material and workmanship for desired advantages. One-piece forged Inconel®-751 Super Alloy offers uninterrupted grain flow for head stability. High Nickel content alloy is a must for extreme exhaust gas temperatures and turbo applications. Hard Chrome Plated to provide a compatible hard surface for Inconel®. “Super-Finished” stem allows for Formula 1 level coating consistency. Dimensionally controlled production tolerances for outstanding consistency. Every surface is either CNC machined or ground as top quality valves should be. Swirl polished or CNC machined profiles are flow bench tested for optimization. Street, Strip or Track. You are choosing extreme durability and performance. Detailed Specifications: Type: Valve spring kit, intake only. Description: 40# seated pressure / 148# at 0.440" valve lift / max lift 0.440". Valves: Valve, intake, Black Diamond™ (Part #30-30220). Retainers: Retainers, intake, titanium (Part #30-31211). Keepers: Use O.E.M. Springs: Valve springs, intake, Kobe Super Clean chrome silicon wire (Part #30-31213). Basewashers: Basewashers, intake, heat-treated steel (Part #30-31215). Seals: Use O.E.M. or KPMI 700-100016 red Viton seals may be used as an upgrade. Notes: For applications with low hours and / or apparent intake face recession and exhaust components that meet factory specifications, consider Kibblewhite's Intake Only Systems when performing necessary service. Bear in mind that Kibblewhite does not advise partial conversions on race bikes and / or engines that have reached factory advertised service limits. Always consult with qualified professionals suited to inspect your machine.