So, it's cross induction between low voltage wires.... Have you ever seen welding cables or jumper cables dance when in close proximity? High current flow through the conductors creates such a strong magnetic field around each cable that the fields interact, causing the cables to move relative to one another. It's very entertaining.
I would attempt to resolve the issue, first, by rerouting the HEI B+ lead. If you have to approach other wires, cross them as close to 90° as possible. As you discovered, do not route the B+ lead parallel to any other wiring. The next step would be to install a high value capacitor as close to the distributor as feasible. The MSD filter previously mentioned is the smallest capacitor that I could recommend for the purpose. The greater the capacitance, the better. The third step would be to pick up a large doughnut shaped ferrite and wrap the HEI lead through the center of the ferrite 10+ times to create a toroid choke (images). Space the windings evenly around the perimeter of the ferrite. The fourth step would be to shield the B+ lead in woven, tubular copper shield, grounding the shield at both ends. As an alternative, you could run the B+ lead through flexible armored conduit grounded at both ends.
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