Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
Why new body, how bad are the scores? If the piston is still a reasonable fit the body is serviceable, its the seal that does the work which you would be replacing anyway on a rebuild. A stainless piston can easily be made on a lathe, I have stainless bar if you have a lathe or a mate.