I have to put in my input on this. I work on all kinds of engines and get alot of stuff given to me that is old and frozen. I feel I've done this a hundred times. I always pull plugs, blow air in holes(make sure nothing is living in there). Pull valve covers and inspect valve train for rust. Put generous amount of auto tranny fluid in each cylinder and start rocking crank back and forth. I have usually never been able to break one by hand so dont be afraid to use a bar. These things arent pianos. Just dont use alot of force at first till you get some movement. Then back and forth. After I get full rotations I change the oil,(pour some on the valve train too) hook up battery and free spin it without plugs to clear some tranny fluid and let engine run in some, and blow grundles out the plug holes. Then put plugs in it and fire it up. Since I used tranny fluid it fill fire with gasoline and not just instantly foul plugs. It will smoke like a chimney at first but the tranny fluid will burn off. I have had say a 90 to 95 percent success rate doin this. If this doent work the engine usually needs rebuild. Tranny fluid also works great to get an engine started with low compression say from sitting a long time. It seals the rings and valves and allows the engine to start. Then it burns off and your good to go.
