As I understood it the external ballast is required for when you install spark plugs that do not have an internal resistance, otherwise no. That’s what I’ve read researching the same concerns. You are reading incorrect information. The purpose of a ballast resistor is to reduce the amount of current (and voltage) flowing through the coil primary winding and the points in the distributor once the engine is started. Makes the points last longer.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12
'52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
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