I would plan to go ahead and go through the engine completely or at least try to get a leak down reading on the "good" cylinders if there are any before you pull the heads... Pull the trans pan too and check for "Stuff" in the pan, or at least service it, check the tansfer case and other fluids as well... Get a big friggin bottle of tylenol, tums and valiums... you may be instore for some fun...