Now you tell us it locked a cam? My bet is on the fact the cam journals are damaged, the head is puking oil pressure past the damaged journal, coupled with the fact the screen has metal. Shit I'd say take it to someone who can diagnose this, but also you say the engine was rebuilt 500 miles ago! Could be issues with rebuild, what about the engine builder? Can he help you? Man so many questions now.... Most likely if it did lock the cam, fixing that head will be more expensive than replacing it with another.