More food for thought. After a recent valve job, I could not get enough lash on several valves. I'm using Schneider's cam, springs and retainers, The billet was new when I first installed it. Then I discovered that several rockers were touching the retainers on the outer edge and were actually pivoting on the retainer and not on the valve stem. The solution was easy. By sanding/smoothing off the underside of the rockers, I was able to get the proper lash. Several of the rockers had small "nicks" on them, indication to me that they had been touching the retainers before I refreshed to top end.