I have a question regarding your engine work, Did you just re-thread the stock cylinder head stud boss and install screw in studs?
If you did , I have never seen that done without needing to machine the top of the head boss flat, if memory serves without doing the machine work the screw in stud sits too high and will not allow proper valve adjustment and the stud will not stay tight.
If it was not required you might have a new style stud I am not familiar with, Just asking ....
Here is a video link to show you what I am referring to.
Desert