Need help-polaris 850 engine won't spin once crankcase half torqued down
So I'm in the middle of rebuilding my buddies 2017 850 sportsman engine. It ingested water, he thought he got all of out but didn't, engine didn't sound right, so he shut it off and pulled it out. I took the engine apart, had some scuffing on the pistons, and the main bearings looked bad, and crank was scored. So I got a new crank, and bearings. Reassembled the engine, spins freely. As soon as you torque down the bottom crankcase cover it doesn't spin, and feels locked up. It didn't spin a main bearing or anything like that when he had the issues. So what am I missing?? Thanks!!