If you feel this site provides you value, and wish to help keep the lights on, feel free to donate by clicking the "Donate" PayPal button.
I believe that the shafts have a stamp/punch/mark that is supposed to go on top, and toward the head (inside edge, not outside edge toward the valve cover), when you install..... or maybe I am misremembering (but NOT like Brian Williams!)
I think this is explained by Clymer that states to position the rocker arm shaft so that the punch mark is facing away from the engine for 1980 on bikes, so early ones don't have it.