Description Reviews Supertech BMW B48/B58 42 x 10.045 (+0.015) x4.985mm Intake Valve Guide - Set of 8 *** Only Fits B48! *** Supertech valve guides for MINI B48 applications are designed for racing reliability and high-RPM use. Specs & application: Intake, Size: Standard, Length: 42mm, and Outer diameter: 10.045(+.015mm). Manufactured from high-quality Manganese Bronze for sport-compact applications, with copper-alloy guides available for high-output exhaust applications requiring superior thermal transfer. Designed to pair with Supertech's low-friction black nitride valves. Replace original guides during any cylinder head rebuild or valve upgrade for proper valve stem support and oil control. Pair with Supertech valve stem seals and valves of the appropriate size. Machine to final ID after installation for correct valve-to-guide clearance. Note: Sold as a set of 8. You will need Exhaust Guides also to do a full head. Exhaust Guides are a different size.