We winterize around 300 boats a fall here, I would change the oil, and pull the inlet hose and run 5gal of RV antifreeze thru after you warm it up and open the tstat. Don't let the block sit empty it will rust. If you're in a pinch you can pull the drain plugs. Should have 2 block drains 2 exh manifold drains, water pump drain and yank the line off the trans cooler and also drain your strainer. But beware, those plugs can only go in and come out so many times. Threads rust and then you'll be getting a heli coil.