Your ignition problems are most likley caused by what the MSD guys call Noise. It happens when you use an unsheilded trigger wire and run it near a high voltage wire, the magnetic lines of force that eminate around the hot wire soak into the trigger wires and confuse the signal. Use a sheilded wire and route far away from any power sourse,
Now the reason you are not getting any spark from it on bench test could be as simple as a good ground to the box.
Also, remember to run a good ground to the MSD from the Head of the car. It makes sense as you are sending voltage thru the plugs, screwed into the heads.
Al