Don, congrats on getting the engine pieces back, looks like an engine building party at Don's place soon. I don't want to start a 'best cleaner' on your thread but I'd like to recommend one of my favorites, it's called LA's Totally Awesome. It's a safe to use concentrate that works amazingly well on many surfaces, you won't believe what it does to aluminum parts. I found out about it on an LS1 forum, those guys recommended it for cleaning the gunk off the all aluminum LSx engines. It's very, very cheap to buy, available at most Dollar General stores and these other stores. Try it, you won't be disappointed.

Mike