Both shafts on both heads will be oriented exactly the same. Just as there no "left" or "right" heads, there are no "left" or "right" shafts. The heads are not mirror-images of each other, they are both identical. As-installed on the engine, the shaft notches always point down, and are at the front on the drivers side head, and at the rear on the passenger side head. If you are not sure if the shafts are installed correctly, the small oil holes always point down and "out" towards the exhaust side of the head. I have seen shafts with no notches and even some notched incorrectly, so the best thing to do is check the orientation of those holes.
