Disconnect the coil from the powerpack (properly called an amplifier). Remove bolts from coil. Now rotate entire coil & spark wire assy to unscrew it from distributor cap. Remount coil and reconnect it to amplifier. Rig up a spark gap off end of the spark wire. Now disconnect black/white wire that goes between amplifier and breaker plate and brush or tap it against an unpainted grounded metal part (with ignition key turned on). That should cause sparks to occur across the spark gap you rigged up. If it does, everything is working up to that point and the problem is under the flywheel (points, rotor, cut-out ring, dist cap, etc.)