HEI Coil- E-core vs canister

Look for KitCarlson's posts which discuss this. I think he would agree that the max voltage spec isn't that significant since it doesn't directly relate to the energy per pulse. The primary resistance probably relates more to energy since lower resistance is more current at dV = 12 V to charge the coil and energy = current * dV. I think the max voltage is important in telling how wide a gap the spark can jump. That is harder at high cylinder pressure, i.e. WOT at low rpm, which is where you might first experience spark miss, and why turbo engines usually spec a smaller spark gap. With a good ignition system, you might be able to run 60 mil spark gap without missing.