New Ignition coil, rotor, and distributor cap, but no spark. Need help.

Your signature line says you have a 66 so I am assuming you still have points. Check to make sure the points are still opening and closing as the engine cranks. The adjustment screw could have come loose and \6's have been known to eat distributor drive gears.

If the car has been converted to electronic ignition it could be either the pick-up in the distributor or the ecu.