Autopsy complete. Results
I'm pretty sure I found the problem. I re-assembled the the top end today, put a couple of rockers on and measured my lifter pre-load as best I could. By that I mean I didn't have a feeler gauge wide enough that would fit in at the lifters with the pushrods in. I measured .045 and still had lots of play. I'm am just guessing but I would bet that there was at least .080 of pre-load.
I figure there are 2 ways to cure this. Shorter pushrods or adjustable rockers. Anybody got any other ideas?
Jack