KIBBLEWHITE Spring Kit - .650" - Evolution/Twin Cam 20-21650

If you're running Evolution or Twin Cam heads, valve wear directly impacts performance, reliability, and your bottom line—especially under high RPM or boost. The KIBBLEWHITE Spring Kit converts your head to stainless steel Black Diamond™ intake valves, extending valve life up to 4x longer than OEM titanium components while maintaining precise tolerances for consistent combustion. This is a purpose-built conversion that uses the same engineering rigor as professional race programs, backed by finite element analysis and proprietary valve train software.

Every component in this kit is engineered for durability without compromise. You get forged stainless steel intake valves paired with premium heat-treated wire springs and titanium retainers—the same materials and methodology used in high-performance engines. Installation is straightforward on compatible heads, making this a smart upgrade for anyone serious about extending engine life and maintaining peak valve train performance.

• Stainless steel conversion kit
• Black Diamond™ intake valves
• Forged one-piece construction
• 4x extended valve life
• Chrome-silicon wire springs
• Ultra-light titanium retainers
• Hardened steel bases
• F.E.A. engineered design
• Application-specific fitment
• Evolution/Twin Cam compatible
• .650" lift specification
• Made in U.S.A.