OK folks the problem was the chain tensioner.
First it went bad causing the guide to be broken. When I replaced the tensioner it failed to expend when the engine started and was totally ineffective.
It appears that when the oil got hot the tensioner was sliding out of its channel and was being slapped back in by the chain making a horrible clatter.
I used a piece of soft plastic to keep the tensioner compressed in order to install it. I had hoped that it would melt and as the engine got hot allowing it to expand. But as soon as it started it expanded I guess from the oil pressure.
Now all is well except a broken guide but absolutely no noise.
The oil pressure reads 20+ lbs at idle so I guess that a good reading.
The slight misfire resulted from the plug boot being saturated with oil. The valve cover inner gasket was leaking and oil was getting to the base of coils.
However I would still like to know if the guide could be replaced without moving the chain. Can anyone answer this question?