Okay maybe someone here can answer this. I have been building and adjusting motors and adjusting lifters forever. The other day I noticed that my rockers were tapping so I pull the valve covers and every other rocker is getting oil, the oil pressure is fine and there is no blockage in the passages. Also the furthest down the line 2exhaust is getting oil. It does this when cold 70psi and hot 40psi. It also will not flow out of the rockers even if you loosen them all the way and yes I just put in new lifters so thats not it either. This will make you say hmmmmmm, thanks

One more thing, Is it possible that one of the lifter bores have worn and the flow is dumping but the pressure is staying up? I ask becuase I have a circle track racer friend that tells me that they bore out for a bigger ford type roller lifter and he said its unbelievable how many degrees the lifter bores are out on gm production blocks. This is the strangest thing I have ever seen., thanks again