"Anytime you pull the head you might as well replace the valves, valve guides ect.. " I don't agree. If the parts are within spec, there is no advantage in replacing them, and depending on what machine shop is doing the work, by replacing the valves and guides, they can quite possibly make the head worse than before. Not all machine shops are qualified to work within the specs of some OE's. MBZ diesel being one case in point.