Doc here,
You can get a EGR block plate Here:
EGR
Sounds like , from ALL the problems you have posted on this engine, It just might be prudent to pull it ALL the way down and rebuild it..have the machining done AND you want to get the shavings from that smoked cam out of the system anyway..Start again with a NEW fresh engine.
This old one seems to be falling apart one part at a time...
Doc