well Atomic may be new shafts, but crow are def regrinds! we have had alot of problems with shimming cams as the lifter recess in the head are all different depths. meaning they all require all different sized shims. the stage 4+ cams are huge compared to fg cams. I dont think you can use vct on them! stage 4 is the max you can go with using the vct. here ya go jet, bit of reading for ya http://www.atomicperformanceproducts.com/camshafts.html