Sideways

As the question states, early head on late engine. I know the smog control crap would eliminate the later head on an earlier engine in some circumstances. They use the same head gasket. Crank sensor would transfer with the valve cover. What am I missing?

LostMotion

I am using one. You have to seal the air ports from the outside on the PY heads. Mine were threaded and allen bolts were installed I believe with a permanent lock tight. The inside air ports can remain the same. There is no flow advantage to welding them shut.