first thing I would do is use a cylinder leakage kit/ gauge and check leakage that way first. hear air through the intake, then intake valve open,noise out exhaust-then exhaust valve, air leaking through the crankcase, then piston/ ring problem.rings are groove location specific and dots up. if leakage is present through a valve, then try again with rocker arms off.eliminate pushrods, or could also point to valve timing.