I had the same problem and thanks to your great illustration, knew the MSD O-ring was in correctly, but it would not close the gap. An added O-ring tilted the MSD O-ring, so I sliced a bunch of hi-temp electrical tape to the width of the land around the dizzy shaft and wrapped the pieces (each about 12 inches long) around to build up the diameter of the shaft....this gave the MSD tapered O-ring a bigger base to go around and made the overal O.D. greater and it fit snugly back into the hole in the intake. I admit, I had to turn the
oil pump shaft a few times and give it a good clunk into the hole but it now fits and doesn't leak!! No RTV. Good luck.