Hey all!

So My 4.6L 2v is back together and the engine is in the bay. When mating the Trans and Engine, I checked the Torque Converter to ensure it rotated freely and it did.
Got the two mated, maybe a half-inch gap? Pulled the two together by tightening the bolts.
Attempted to rotate the crank with a prybar on the crank pulley and wouldn't budge.
Pulled the trans back out an inch or so and couldn't get the TC to rotate by pressing on one of the studs with an open wrench.
Crank was still stuck as well. Pulled the trans back out completely and everything rotates just fine.

TC is seated as much as I can tell. Pushing in and rotating slowly clockwise, will not seat any further.
I'm about to put it back in again and cross my fingers, but was wondering what else I could check here?

Saw something about removing TC and checking Trans Oil Pump with a screwdriver?