I had a 350 that had set for 7 years. All we did was squirt some penetrating oil into the cylinders, and let it set for a week. Then we turned it over by hand a few times, ran the oil pump with a drill. We then hooked the starter to the 24 volt jump-off port on my m-1008 pick-up, and spun it over a few more times. Rust and carbon blew out of the spark plug holes, all over the wall in the shop. After that, we put in some new plugs, wires, and gas, and it fired up.

I'm not saying this is the right way to do it, cause I wouldn't do it again, I'm just relating a similar expieriance.