Start with a level foundation. All this crap is why, when you do a head, you check the head surface to valve spring seat surface. Then you measure every valve length to see that they are the same overall and tip length. Measure all installed heights, then do the valve job to make all installed heights to the tallest measurement. Know what to do to blend the combustion chamber to the seat in the head. Replace the seats in the heads with hard seats if something is sunk beyond proper measurements or throw the head away and start with a good one. Or you could buy a lathe and cut 16 different push rod lengths to get uniform preload. Yeah, adjustable rocker arms are an option, but the head is still all screwed up if you don't start level. And you don't think knowledgeable engine shops are worth the money? I know, too damn expensive! Wanna race?
