A crankshaft with all its' caps bolted to spec torque should easily turn by hand. As each piston is installed, it will take more torque to turn the crankshaft due to the drag from the cylinder walls, especially with new rings and bored/honed cylinders. Make sure piston ring end gap is correct. I lube the cylinder walls with 10W-30 during assembly so the engine will turn over easier. I cannot turn over a freshly rebuilt V-8 just by grabbing the damper, usually requires a power bar to turn things over.
