When reinstalling the distributor in my 1954 235, it seems that the only thing that keeps the shaft down in the oil pump is being careful to get it down in the pump slot, then that little metal clamp around the shaft, with the 1/4 inch clamp screw. Seems possible could get the rotor shaft gear engaged,so engine would run, but not the oil pump. Or could it come loose? Am I missing a more positive hold-down? Also, what's an easy way to line up the pump slot? What a great site, thanks to all you experts!