273 Rockers on a 360

just for giggles lock a valve at half lift with a clamp around an old stem seal
put the rocker on and see if the line between the valve tip/ rocker pad through the center of the shaft is perpendicular to the stem or parallel to a retainer, use a machinist rule and eyeball it from the end
you easily will see if your shaft is too high or too low
then measure pushrods after you get shaft located correctly