If you're lucky it's just a few rings stuck to the cylinder walls. Let'em soak for a few days with a good penetrant and try again. Bolt up the converter as much as you can and use a pry bar on the ring gear to get it to turn Going through the starter hole seems to work the best for me. If you can't break it loose that way, the starter's not going to do it. You'll have to pull the engine down and re-ring the thing. Even if you unstuck rings it may smoke anyway.....
