My Motor manual lists a 25 and a 30 amp generator for Chevy from 55-62. Olds, Buick, and Cadillac specifications show generators up to 45 amps. A note about the Chevy 30 amp system indicates that it uses a "double contact" regulator and cautions against grounding the field circuit with the field wire attached to the regulator. Apparently, the 25 amp generator does not use the double contact system. That should be easy to check by removing the regulator cover. The 2-contact setup will be behind the "F" terminal. The 30 amp generator will work OK with a 25 amp single contact regulator, but you'll lose 5 amps of charging current against a very low battery. Not a problem unless you have a lot of high current draw accessories, or you're in the habit of leaving the lights on with the engine stopped and running the battery low. Good luck!
Jerry

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