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Its difficult to tell from a video, but you have lots of lift. Check your valve springs when they are compressed and see how much clearance you have between the coils. Are your rollers right in the center of the valve stem? The water could get in from the breather not headers. No big deal there. Were all the pushrods the same length when you installed them? different makes are slightly off when they are mismatched. Do you hear clicking from the valve train when its idling? Are those dual or triple springs, the inside ones could be binding.

Oh make sure the motor is warm when you check the clearance, the lifters are pumped up as well then.