Pulled head off 1928 Durant M2 W5 engine yesterday. Pistons and cyl walls are really like new.#3 has one teenie scratch, But not enough to worry about. Looks like head gasket leaked between 2 and 3. Question is, I will send head to machine shop for cleaning and to check for any warp, but how far can it be machined down to trim back to true? Also is there any way to clean rust out of block and ports before reassembly? I don't want debris pumping into new radiator. Please advise. Gregg