Freeing up a stuck engine

[gmcbigbl]

I just bought a older vehicle (1972) Chev. pickup and the V-8 engine is froze up (stuck) and won't budge at all. I pulled all the plugs and put Auto Trans fluid in the cylinders and let it sit for a week. Pulled the radiator and I have a socket on the crank pulley with a persuader bar and a pipe trying to turn engine over, but no luck. Anybody got any more ideas how to get engine to turn over? It's an auto trans and don't really want to try to tow it to turn the engine over.