Fitted overdrive trans and need to find a starter motor to fit.

Looking at your picture again, compared to my 273 on my engine stand, they need to look and make sure the bellhousing is lined up right. I don’t see how it would fit cockeyed and the converter hub not hit something, but they have the bottom bolt by the starter location in the wrong hole. The dowel pin goes in the 2nd hole up and the motor to bellhousing bolt goes in the bottom hole.
My picture didn't tell the whole story. this block has 3 holes. I think that's the issue.

The slightly earlier 318 Poly that was mated to a cast iron Torqueflite had a smaller recess in the rear of the crank. I lucked out with this one. As above, I think it is a '67 model but the '66 with aluminium 727 would have had the same crank.

starter 2.jpg