Overhauling the cylinder-head valve train will always give more reliable results with as many items as you can possibly afford are renewed. Top flight race engineers don't repair the old inlet and exhaust valves, springs, seats, collets, retainers and tappets - they replace them all with new. They get a hammering literally and metaphorically after all!
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Renew all the wear parts in the valve train for the best results. Order gaskets, O-rings and sealant (try this professional gasket seal 08CRAHLG120G) at the same time?