putting bigger valves in theses head changes alot of things i learned the hard way and paid for it too be rectified ! heres what happens in the wrong hands ! (We have checked the valve spring pressures. At fitted length they are 55.6 to 58.4 lbs. Over the nose of the cam they are 124 to 126.5 lbs. which is very low, especially for a turbo charged application where the boost pressure is lessening the poundage on the inlet valves. You may risk valve blow by on high boost. Coil binding occurs at 0.80 inch. At the current fitted length you are 0.225 inch off coil bind at full cam lif