well...from the sounds of all of it...i say resurface the head and block...not sealing properly?? maybe with one of those overheats you warped the head?? aluminum is pretty easy to warp if you overheat it.

i personally feel from experience with v8s your overheat problem may have had something to do with your head gasket change...im assuming that you are changin it because it was bad, and it could have been leaking coolant too and you not notice it...remember with the open block design there really isnt much that seperates the coolant from the cyl other than the head gasket. it could have been air too...but i thought teggys had the air bleed plug on the upper radiator hose connection on the engine vapor lock happens...its all something we have to deal with, but there are ways around it. like running the engine with the radiator cap off and keep putting antifreeze in it after the thermostat opens...stay on top of your engine bro. i think your head gasket may have just be the whole problem all together

did you check the cyl walls for cracks??