[fsiewert]

Try unpluging the distributer and put an analog volt meter between the two conections on the wire from the distributor, on the miliamp scale. The needle should move as the motor is spun with the starter. If not replace the magnetic pickup. I have seen the magnent in the pickup cracked and it didn't produce enough voltage to activate the duraspark.

OR
See if Pertronix makes a pickup unit that fits in your MSD Distributor. Then you will be able do away with the Duraspark.