"Charlie" has Overheating probs- Here are my Clues and please chime in with opinions!

If you can get a pressure washer in there it might help. Pull the water pump and try to blow it out the freeze plug ports. Use a hanger in between pressure washing it out. Fish the hanger or welding rod in the freeze plug ports, and dig, every little bit that comes out frees up space for water. Otherwise! She has to come out. Fresh bearings, a dingle ball hone, rings and gaskets, a chemical dip, and fresh cam bearings, she'll be as good as new.