As valve guides age, they lose their ability to locate the valve to the valve seat. That can create a loss of performance due to the ineffective seal of the combustion chamber. Be sure to replace your guides when replacing valves, valve springs, etc. High-quality OEM replacement, designed to perform like the original. We source this part in Germany to ensure quality, reliability and precise fitment. Sold individually. 6 necessary per vehicle for 911's.

"Valve Guide - Intake / Exhaust - 1st Oversize - 8.9 X 13.26 X 51.1 Mm"