As has been asked, if it's just the crank it should turn smoothly with a light drag. With the rods and pistons etc on there then you will need a barring socket on the end to turn it. there will be quite a bit of resistance to get it moving and then will need a firm turn to keep it moving.
If it is just the crank you'd better take the caps off and make sure the shells are seated properly. Before you do that though, give the crank a firm-ish thump with a soft hammer to seat the end thrust bearing.