??Distributor shaft depth in oil pump drive??

Have you measured the actual distance from the top of the block where the distributor sits down to the intermediate shaft itself?
I see the contact area on the distributor shaft, but I'm wondering if it sits further into the slot than the contact mark itself is suggesting.
Incidentally, one of the large engine mount bolts from a Magnum equipped fullsize Ram is the perfect size to use as a puller for that bushing. It threads in tight enough and has a flanged head, so you just use two pry bars to evenly pull the bushing right out.