’67 912s have generators not alternators.
J & J are both right, though J is more right than J. Generators equipped cars often show red at idle & though it doesn’t necessarily mean bad regulator or gen it isn’t right. Both need to be checked as does your fan belt, & grounds
The biggest benefit of alternators is that they don’t “run” all the time. The biggest benefit of generators is that they don’t need to be excited to put out
Obviously car manufactures thought the extra HP was more better
