Jimmy,
Since you had the engine out and disassembled, there are just too many variables at play for us to guess what might be keeping it from spinning freely.
You will just need to trace your steps back (with the service manual) to find what is causing the problem.
Since the 'no turn' problem only came to light after you put the engine in the frame, maybe there is something loose in the sump that is now wedged somewhere. .....
Let us know what you find please, or if you get stuck along the way.