If you've got spark at the coil, then it's not the ballast. Look at it in its simplest terms- you have spark at the coil, and nothing at the plugs. It disappears somewhere between the two. The path from coil is: coil wire-distributor cap-rotor-distributor cap again-plug wires-plugs. If no spark to ANY of the plugs, its disappearing at or before the rotor. Provided you replaced the cap and rotor with the correct parts, that leaves one thing: bad coil wire (or bad connection).
Make sure the terminals of all your plug wires are seated firmly into the distributor cap and coil, and the boots aren't keeping the wires from getting pressed all the way in.
