I might add that a good scrubbing of the new block should be done. Any sand from the casting process that finds it's way into the
oil is a very very bad thing. Sand in the coolant isn't good either.
Paint the outside first so you don't have to fight the rust and how do you get paint to stick if you get
oil on it issues.
You cannot clean it out too much. Soapy water and every scrub brush, bottle brush, and gun bore brush you can find, is where I start. Especially the
oil galleries. Blow all the water off with a clean air source, and get some WD 40 to lift off any moisture and wipe it down a couple times to keep it from rusting.
Also make sure the oil areas of the heads are clean too.
Ovoid rags that make lent when you rub on a cast surface.