Surface rust

My parts engine/truck is sitting outside, I opened the hood to find a coating of surface rust on the deck and in the cylinders. Its been raining here hard last few days off and on. Getting in there somehow.

I am concerned with the humidity that the engine in the truck I care about may also have problems, its prob. going to be sitting a few months while I am working on my education of these slants.

What do you guys recommend as a coating. I dont think oil is going to cut it. Someone recommended something to me while talking on the phone but I cant remember what he said.

Id like to get something in there down in the rings ect so I dont have any problems.