Precision C630 Guide, Int/Exhaust +0.001

Guide profiles are designed to be as clean and unobstructive to the airstream as possible, while maintaining critical cross-sectional thickness in high-temperature areas, promoting both high performance and endurance. In many instances because of the nose shape, just the installation of the guides with no other modifications will enhance airflow. Where the factory base washer allows for it, guides have a flange that sets the protrusion at a height that allows for correct seal-to-retainer clearance for the most aggressive cam available at the time the guides are designed. Once the flange touches the head, you're home. No time lost stopping to measure guide protrusion several times during installation. In cases where a flange would interfere with the factory base washer fitment, a small decrease in diameter above the purchase area marks the correct guide protrusion. Very tight concentricity tolerances are held to ensure that the best possible geometry between the seat and guide is maintained when the guides are replaced. This means minimal material removal from the seat, time savings, and consistent chamber volumes, when valve jobs are performed with KPMI guides installed. Material is mill certified, guaranteeing a consistent premium grade of material in every production run. This unique blend of materials create a guide that is extremely resistant to galling, which allows for tighter clearances than other materials. This reduction in clearance creates a better valve-to-seat seal and superior oil control.

C630 Racing Bronze material contains 80% copper alloyed with 5% nickel and 10% aluminum. High copper content (20% greater than traditional manganese bronze materials) gives excellent thermal qualities. Engine Builder C67410 Manganese Bronze Valve Guides were designed with the price conscious builder in mind and meets all the KPMI dimensional tolerance and design standards. The bronze alloy offers good high speed anti-galling/seizure qualities with a 60% copper content for increased thermal conductivity over iron guides . Manganese guides are not quite as hard as the C630 bronze but can be reames to size with a carbide reamer. High nickel content makes the guide harder and more wear- and corrosion-resistant than other bronze materials. Corrosion resistance is an especially critical element of guide life with the new pump and performance fuels sold today. Aluminum content brings characteristics that make the guides especially compatible with aluminum cylinder heads.. A radius at the transition from the nose profile to the main body of the guide prevents galling on installation. Kit includes two valve guides unless noted.