Ford Repair: roller rockers, roller rockers, lock nuts

Question
I have a 1991 mustang wich i have had the motor rebuilt.I have put a aftermarket set of heads on.I have installed a hyd.roller cam.The car runs fine but i cant stop the motor from taping and i keep adjusting the roller rockers and it still taps.I have spent over 10,000 dollors on this motor and no mater what i do it has a small tap coming from the valve covers on both sides. I need help.

Answer
I wouldn't drive it much if its taping.  I had a valve tap on an engine and it ended up pushing the valve keeper out and letting the valve suck inside the cylinder and waste a good engine.  Try adjusting the valve train while the motor is running.  I use nylon lock nuts on my valve train to keep it from loosening up.  Other than that, i dont realy know what to do as ive never had a problem with a valve tap that i could not fix.  set your lash while the engine is cold, then start it up and set it again while its running. You can adjust the rocker untill you no longer hear the tap.  Also remove the intake and check the lifters.  Its not easy to tell if there bad or not but you may need to replace them.  Also make sure you have plenty of oil pressure as poor oil pressure will allow the lifters to collapse.