A few days ago I herd a Knocking sound coming form the air filter. Man I was worried, the last time she did that my cam had rounded off a lobe and chewed out the cam bearing . I then removed the vale covers and put her on tdc I found the problem. I had two intake valves that were way lose, and a nother on the 360 turn. She sure dose run smoother and the knock is gone,that the first time I checked them in 50,000 miles after the rebuild. Holds boost longer to think goodness.