Pontiac to Early cad adaptor question.

I was at a friend place today, and picked up a couple of early cad stick bellhousings marked 1951. One of these was bolted to an unmarked adaptor. Does anyone reconize the bolt pattern. I tried it on a chev with no luck. Its painted Pont blue and has similar bolt pattern, but the starter is on the wrong side. Anyway maybe some one out there knows.

 

It allows a '49-'54 Cadillac bell housing to be bolted to a '55-'62 Cadillac block.

 

Many thanks, One reply does it all.