KPMI, exhaust valve guide. C630 bronze. STD

C630 bearing bronze. Size: 0.5620" O.D. (14.27mm); 0.3090" I.D. (7.85mm); 2.00" OAL (50.8mm). Comes with special shoulder for ease of installation. Takes OEM valve seals. Shortened to accept valve lifts up to .600". C630 bearing bronze is a tough nickel-aluminum-bronze alloy typically used in High Performance and racing applications where rapid heat transfer from the valve to head is important.