Put it all back together with no head gasket and zero valve clearance with the cam you plan on using. Then measure your piston to valve clearance and see where you are at. Try to keep clearance at .090 . My guy at the local shop told me that i could .030 on relief if my clearances was too close. Take a old stock 27mm valve and cut notches in it with dremel tool , put back in head and start cutting relief in piston but a little at a time. Keep checking your clearances, don't go too far but don't do too less. You will get it right, takes time is all.