KIBBLEWHITE Valve Guide - Intake - +0.010" 40-41629

Valve guides wear faster than most engine components, especially under sustained high-RPM operation or boost pressure. A worn intake valve guide introduces excessive valve-to-seat play, killing compression, leaning out the fuel mixture, and allowing oil to seep into the combustion chamber. The KIBBLEWHITE Ampco-45 intake valve guide eliminates that slop with a precision-engineered fit and material composition designed to outlast factory guides in demanding racing and high-performance applications.

This +0.010" oversize guide is constructed from Ampco-45 bronze, a copper-nickel alloy that dissipates heat away from the valve stem faster than cast iron or aluminum alternatives. The high copper content (80%) delivers superior thermal conductivity, while 5% nickel reinforces wear resistance against the constant friction of valve actuation. The result is a guide that stays dimensionally stable across temperature swings and resists galling even under aggressive cam profiles or forced-induction loads. Manufactured in the U.S.A., this guide meets the precision standards required for serious engine builders and professional racing operations.

• Ampco-45 bronze construction
• 80% copper content
• 5% nickel alloy
• +0.010" oversize
• Superior heat conductivity
• Enhanced wear resistance
• Precision-engineered fit
• U.S.A. manufactured
• MPN: 40-41629
• Intake application