I'll ask a dumb question, was there a cover on the bottom of that bellhousing?

That brings up a good point. I drove my car around with out a bottom cover back in the day. A tire threw a rock up and the flywheel grabbed it and sent it up and threw the top of the bell housing. Great big window in the top of housing.
As to his question about offset dowel pins. I heard the bell housings were line bored on the block when they did the line bore for the crank. And to back that up the service manual states that any time that a bell housing is swapped from another motor or Damaged it should be checked for runout.Your only allowed .004 runout, I think if I remember right. You know looks like it broke the crank flange also.