Ok, so I have an engine that had a 5spd behind it and am trying to bolt up an automatic. It appears that the end of the eccentric shaft is different!!!!

Believe you me, I would rather have a manual, but I am not cutting up the tunnel to fit this 5spd in there.(it's a '73 rx2) Has anybody heard of an adapter to go this direction? Or do I just have to bite the bullet and rebuild my original motor?