I have a pretty good success rate with this.. which is pure luck really.. by soaking the cylinders as previously stated and doing all of the things you are doing. These engines are very resilient. But I think these days, just to be safe, I would pull the side cover and make sure that as the motor turns, the push rods also do. Why the side cover when you can see it at the top? Because you can see if the rods are straight and not obviously bent, or bending when you rotate the motor.
Later you will want to put a garden hose to the engine blocks water jacket to the drain cock fitting on the drivers side rear of the block. Lots of times that is all stopped up. If it is, your engine will not cool properly. Whatever you do have fun!
You will find a rebuild document below. Maybe there is something there that will help you decide how far to take this!
http://devestechnet.com/Home/Project1959235
