Noisy Valves

[spudz29212MKIII]

Hey guys, im having a issue with some noisy valves. I did the ole broom stick trick and the noise is loudest on the exhaust cam side. I forgot which one its technically called but im guessing its a tap, or tappet kinda like a bunch of marbles in a can.

There is no noise on decel or accel but lately I have been hearing it slightly at the start of accel. I have a turbo and my boost gauge is showing a slight vacuum leak at normal speed then when I release the pedal its a quick downward flick to 20hg. Thought this may be sticky valves so I did a one day pedal to the metal crankcase seafoam treatment (which did good in other areas and also ive never seen such horrible sludge come out when I drained it) but I had no luck with solving the noise.

Any ideas on wtf is going on? Clearence? Help is much appreciated thanks.