[rotorwrench]

4-cylinder engines never had a problem with dwell time. It's the V8 that had problems requiring two sets of breakers to increase dwell time. I would doubt if the high tension build would be much higher in voltage with a different breaker cam. If it is, the amount would likely be negligible. An oscilloscope would confirm ya or nay in any case. Coils gain saturation very rapidly and the engine only fires two plugs per crank revolution on a 4-banger. The model A engine is not a real high rpm engine in stock form.