Comments

Bill's suggestion about the coupler is valid and good.

In addition, I would pop the valve covers and finger test the pushrods by twisting them, check the rockers, and look at the underside of the valve cover to see if anything is loose. I had a valve cover trap get loose one day, it scared the heck out of me, it was banging against one off the rocker arms. I suppose you could push a PCV valve too far down too.

If valve gear is good, oil pressure is good, and the noise is unaffected when you pull plug wires, I would think it is the coupler as Bill suggested.

I have heard Paragons start slapping and clanging something terrible when the rpm is very low during a docking manuver. For that reason, I have my engines set at a little higher rpm for docking to avoid that, and to assure I don't stall out when I need them the most.

Good luck, keep us posted,

Paul