Just to condense some info here:

- You personally saw this engine run

- You took it apart

- installed an adapter plate

- Now it does not turn with a breaker bar with the trans off

Things I would look at are clearances between the flywheel and the block including any through bolts and stuff in the oil pan. The chain is not going to bind up if its around the cam or pulled taught. Even if the chain was bound up you would be able to turn in counter clockwise a little and unbind it.