Alternator upgrade needed?

[2011SVT 10]

When I flip on both the headlights and the windshield wipers, at idle the car tries to die. I'm thinking voltage is dropping because the alternator doesn't make enough amperage(?)

 

No markings on the alternator to tell me what the amperage is (which is odd given that this was a 'concours' type restore so I would have expected to see the standard autolite color codes - shrug).

 

Thoughts?

[miketyler 15]

You can check the post on back of alternator while running to see what voltage is coming off of it. I would think you should see 12-14v at idle with no accessories on.