my slant wont turn over!

Ok, so after nearly totally installing said engine (72-225, known runner) after it had been sitting in dry storage for a couple years I am attempting to bolt up the converter to the flexplate and got one bolt in and tried to turn everything over (converter spun freely before bolting together) to install the other bolts and cant turn it over with anything, including the starter.

When I swapped the oil pan everything was nice and gooey due to the person who pulled it, not draining the oil first. The valvecover had some surfice rust on the inside (condensation) and the plug look brand new.

Anyone have an Idea what might be making it bind up?

its a 72-225 in a 64 Dart with a pushbutton