He's a busy chap at the moment so I put this to the forum...... Quote "just to make sure they are settled and the clearances are set at their optimum for longevity. Intakes on the large side of the tolerance exhaust on the tighter side of the tolerance. This is from my experience with these motors that the intakes tighten up as the valves bed into the seats and the exhausts tend to loosen off as the carbon deposits on the valve and seat." Question for the people that have done the clearance on there 990 motors did you find the same, that the exhaust were on the large side so needed a thicker shim. I only ask because I'm doing mine at the moment and the exhausts are on the larger side so they could go larger still not tighten up?