The pull & drag routine is a good way to destroy everything below the pistons- - - -bend connecting rods, break the crankshaft, break axles, transmission, clutch, etc.
The best penetrant I'm aware of is Kroil, made here in Nashville.
www.kanolabs.com Pour 3 or 4 ounces into each cylinder, wait about a week, and you can drain it out of the oil pan and pour it through again. It will creep right through the rust around the piston rings. After a few cycles of soak/drain, put a big pry bar on the flywheel teeth through the clutch inspection housing, and try to rock the crankshaft back & forth. Another way to get a pry bar to the flywheel is to remove the starter, and use the squared-off tip of a carpenter's wrecking bar in the hole, prying against the teeth on the flywheel. Just don't get crazy and break the ring gear teeth off!
Jerry