Replacing the rear main seal. This is the second time. I'm using a speedi sleeve on the crankshaft, and the rubber type lip seal, not the Teflon one. I noticed that the rubber dolls I put in their previously, had climbed up inside the block at least a quarter of an inch. This may be the source of my leak. Other then replacing the rubber dolls again, or squirting RTV up in the holes, why can't I drill, tap, and plug these holes? Any reasons not to? Thanks!