I recently purchased an 03 Explorer that had upper engine noise on the passenger side. turns out timing chain and tensioner on passenger side were bad. while changing the timing chain I bent a couple valves on the passenger side. Jumped a tooth and i turned it over by hand (aargh). The head is all redone and engine assembled. It starts and runs fine not quite as loud as it was before but still has lifter noise on top. I went to check the oil restrictor on the passenger side had in realize that there is not one there. Do the newer 4.6 heads have restrictors? Would not having this in the head cause low oil pressure to the passenger side valve train and tensioner? Im thinking the tensioner and guides went bad due to low oil pressure. Oil comes out of the lifters while running but it doesn't spray all over. I blew out the galleys in the head cam, lifters and restrictor hole and they all seem open. the heads look in the same shape as the 20 or so other pairs I've seen. Nothing is scored but it worries me to drive it too much. Its allready been about 3000 miles.