Factory fresh valve train components to assure optimal economy, performance, low emissions, and smooth running. Anything you can do to keep the bottom-end of the engine together and working well, and then have a fresh and tight cylinder head, you will experience the maximum performance from your engine. Remember worn valve guides can contribute to the premature wearing of new valves.
Next time you have the head off your B18 or B20 engine, have a machine shop inspect the valve seats for excessive wear. Consider installing hardened seats to extend valve life with lead-free fuel use. (For B20 engines, consider upgrading to stellite faced exhaust valves, as used in the fuel injected B20 models).
