I'm bringing up this hi-jacked thread again as a reminder to check your tappet screen. I have a Mastiff in my shop, customer was complaining of excessive upper engine noise. He said he just had the jug gaskets replaced, and it wasn't that noisy before. So I readjusted the push rods, and while it was right in front of me, I pulled the tappet screen, and it was very very dirty. The worst, by far, than I've ever seen. It was probably the reason for the noise.