I noticed a ticking coming from my driver side just a little while ago. I think it's a rocker arm ticking, since I don't have an exhaust leak (that I know of). Can't I take a screwdriver and place it against the valve cover while the motor is running to verify if it's a rocker arm? If so, how dangerous is it to leave this unchecked for a little while? I want to replace the heads pretty soon, and I figured if it is a RA, then maybe I could just wait until I do a headswap that way I don't have to do twice the work. Any suggestions?