Hi David,
I did this to a O360 that was not going to be installed for an extended (still not installed) period of time. I removed the intake tubes and capped off the intake and exhaust ports with rubber gaskets and plywood backing plates. Plugged the crankcase vent. Then filled the entire motor with the cheapest 30wt oil I could find.
Then I turned the motor upside down and left it that way. In this position, you never have to rotate it, everything is in oil... the entire crankcase, cam, rods, pistons both sides and the valves. The crank seal is 100% oiled. The only place inside the engine that is not sealed in oil is the bottom of the sump that has nothing of value in it.... But if you want,you could remove the drain plug and top it off also.......
No airspace = no corrosion.