[rotorwrench]

It depends entirely on what coil a person is using. If it has a helmet type distributor or a later crab/rabbit ear distributor and is using an original type coil depending on application, then it would need the early type ballast resistor used between 1932 and 1948 by application. If it has a can type coil conversion set up then it shouldn't need a ballast if it is a 1.5 ohm primary type coil.

You can bypass the amp meter if needed but I would want one if it were me. Decent amp meters still show up now and then even for 1932 commercials or there abouts.

Charlie's right on about use of a shunt for an old original amp meter that is using a later type generator with higher output. The old 20 amp 3-brush type generators with the cut out didn't need it. the extra length of shunt wire will help protect the amp meter.