49 geezer,
Very interesting. I have no clue if this could be it, but I looked through your engine rebuild pictures just last week and saw something that I questioned.
Again, haven't a clue if this could be your noise, but the rocker arm oil feed line is UNDER the pushrods in the original pix, but in the 'after' pictures you have it outside the pushrods.
I think it belongs inside, snuggled up against the block. Did you actually install it outside the pushrods, and could it be mashed and/or rubbing on a pushrod? Just a thought!
Stuart
