What troubles me about all the suggestions regarding tapping with a block of wood is as follows:

The head gasket is unable to sustain the weight of the front of the vehicle and the block. Pulling upwards with the crane should easily put 1000 lb. of pull on the head gasket. I don't believe there is any possibility of the head gasket maintaining a grip with even one-half this load.

So, lift the head with the crane. If all the fasteners are out, the head MUST lift off the block. There is simply no other possibility.

You may have put 200 lb. into the cables and watched the front end come up slightly. This may not have been sufficient to break the head loose...........