Unlock frozen engine

I want to remove the bell housing on this Gen1 Hemi but its stuck solid. Need to spin to get to all the flywheel nuts. I removed all the plugs today and they looked pretty good except cylinder 1 which was rusty and was the most difficult to remove so I would say that has had water in that cylinder.

Any recommendations on what I should soak the bores with to try and free it up or any other handy tips.