I hate to be a nitpick but you can't calibrate valves, you can adjust valve lash, you may have to experiment with it. If you are having trouble, you should attach a vacuum gauge to the intake manifold, and monitor vacuum levels at idle and try to achieve the best idle vacuum. A stock car will idle at about 21" of vacuum, so use that as a reference. You may have to increase the valve lash to get the right idle vacuum which will mean a noisier valve train. Good luck to you man.