[Synchro909]

If the engine is stuck because the pistons are seized in the bores, you should be able to remove the crank shaft. If you do that, there is no way you'll damage the bearings or bend a con rod by pounding the piston. You'll also only be fighting one cylinder at a time. I'd soak each with penetrating fluid first as described by others. I like acetone with a little automatic transmission oil added for that.