Slow crank

Hey guys need a little help. Just got the motor back in the car and it won't rotate fast enough to fire. New starter and new battery. Battery is located in trunk. Any thoughts on cranking issue? Its a 440 .40 over 10.5 to 1 piston compression with 915 closed chamber heads eddy performer comp cam thumper cam. I don't understand what's going on. Checked all cabeles and connections can't figure it out.