A critical part of any head rebuild is new OEM intake and exhaust valves. Many times valves can be reground and reused, however if your valves are too worn to be re-used, Pelican can supply you with the needed parts for your rebuild. Valve Guides act to provide valves with proper lubrication while your engine is running. Any head rebuild should include new Valve Guides. Whenever you replace the valve guides, be sure to check the size of the original valve guide before ordering.