There are two possibilities, assuming of course that all the correct parts are fitted; compare dimensions and part numbers to anything removed from the car.
Either, the distributor isn't turning or the LT side of the system isn't triggering. First thing to do is turn the engine over with the distributor cap removed and make sure that the rotor arm is rotating. If it isn't, it could be something like the gear on the driven shaft is damaged.
If the rotor arm is turning, check that the low tension side is triggering. You can do this by looking at the voltage coming out of the wiring between the distributor and the coil. NOT the large high tension cable, leave this alone as this carries high voltage. There ought to be a thin wire, possibly from the side of the distributor to one of the terminals on the coil. This ought to "pulse" with the rotation of the engine. This pulse, on a vehicle of this age, is likely to come from the points. Looking deep into the body of the distributor you should see a small cam on the rotating shaft which triggers a contact breaker. If these are in constant contact with the shaft then there will be no spark.
Given the age of the vehicle, this may have been replaced with a solid state electrical system. These systems are all different but typically use an ignition amplifier and the voltage coming out of this can be monitored.