'' However I am surprised at just how noisey it is, it certainly wasn't this bad before I did the head swap''
''Don't underestimate the oil drilling issue. I've known of hydraulic tappets that have been transferred from one K16 head to another and had issues over the position of the drillings. I would think this is the most likely issue.''
I know of 2 standard K16 heads ( including mine!) where the drillings for the camfollower oil feed were poorly positioned, on the exhaust side in my case. The engine sounded dreadful and some cam followers never filled. With the cam carrier off and the follower in place, look down the oil feed hole with some light, you should be able the groove in the follower. In my case I had to open out the bottom end of the oil feed with a Dremel.
Malcolm