I used 400 , it's shinin like a diamond in a pigs ass! I tell yah man, after I cleaned it l? HOLY CRAP! What was once black, is now looking like chrome.
And I SWEAR they painted the inside of the head and the top of the piston. Or, i had some major carbon build up the same color as the engine.I've got pictures but ill post a bunch of stuff when I figure that out. Gotta be simple like you said.