Originally Posted by 46gmcpu
Were the GMC's not originally positive ground and the Chev's negative?

Yes, but the only part that needs to have a dedicated polarity is the regulator. There's a difference in the arrangement of the cutout relay point material that causes rapid deterioration of the points if an incorrect-polarity regulator is used. The generator can be polarized to work either way without any concerns, other than maybe a part number mismatch. The actual generator is no different, regardless of polarity. Modern replacement regulators are often made to work with either polarity by changing a few internal parts. It makes it a lot simpler for parts stores not to have to stock both types. I'm not sure if a dual-polarity regulator is as efficient as a dedicated-polarity one, but they work well enough to keep the battery charged.
Jerry

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