A friend who runs a salvage yard has a neat trick. He removes the carburetor and exhaust manifolds, covers the ports with strips of thin wood or duct tape, drains as much oil as he can, and then he turns the engine upside down. The residual oil that doesn't drain puddles around the pistons and some seeps into the combustion chambers. Years later, the engine is still free to turn with no cylinder rust. They smoke a little on startup, but there's no storage damage.
Another really long term storage trick is to dismantle the engine somewhat, head(s) off at least, and store the pieces in a ring-top 55 gallon oil drum filled with Diesel fuel.
Jerry
