19-04-2019, 05:40 PM
Phil, I was told by a 750 club champion in the early 60s, to tap the valve guide down flush with the port to improve gas flow. And then check that the valve collett collar didn't foul the botoom of the valve guide when vale was on full lift. High lift camshaft might be affected, but I always tap the guides down and have never had a problem. John