help needed with 904

Ooookey, I finally got the motor to a point that I could get it off the stand and get the transmission on. The cooling line holes are plugged and so is the dipstick tube hole. I have a gasket for it and screen. I think I'll start with a light cleaning? Roll it upside-down open it up and take a looksy. Problem is I don't know what I'm looking at ...LOL