Help with identifying various holes on '71 340

Definitely block drain, needs a plug or coolant might come pouring out. Sometimes casting sand covers it and it won’t drain. Needs a plug. I put petcocks in mine. I drain the water after race season and put coolant in it, gets cold in the garage. Actually thinking about just draining it and leaving it empty over the winter. Oh, be very careful with water pump bolts. You put a bolt that is too long in and it can hit the cooling side of the cylinder wall and crack the wall. Very bad.