About 5 months ago I put a fresh, remanufactured Chevy 350 into my F-body. At that time, when the engine was on the crate, it spun just fine. Fast forward 5 months, it's in the car, but I can't get it to spin. I've tried a ratchet on the crank, a pry bar on the flexplate, and even tried the starter to see if it would spin it. No dice.

Can anyone give me any advice or suggestions on where they would go from here?