As has been the case before, one problem was masking another. Yes, the oil flow through the original lifters was sub-optimal, I did test with 10w-30 and saw no noticeable improvement.
But the real problem was the pistons hittng the Edelbrock heads, but barely. Enough to make a racket but, according to my engine guy not enough to do any damage.
Lots of lessons learned here. Had I known to clay your pistons with your new heads, it would have saved me a LOT of time, money and effort. I believed the logo on the box that said "Bolt on and Go".
Fortunately I did have the original 4V iron heads reworked by the (good) machine shop - though at a staggering cost. So those go back on and we'll see how it goes.
And this all started with a backwards head gasket.
