Which alternator 60A or 46A?

My '71 Dart GT (318, auto, A/C) is in need of an alternator. NAPA shows a 60 AMP or a 46 AMP available. What was the factory alternator rated at?

The car has no extra electrical additions other than AutoMeter electric gauges (water temp, oil pressure & voltage) and a tachometer.

Thoughts?
Do not get a "remanufactured" alternator from a parts store; they're junk. You can get a brand-new Chrysler 46-amp alternator from Wallwork. Get a good new voltage regulator, Standard VR-128 or NAPA Echlin VR-1001. Run a ground wire, 14-gauge, from the "GRD" hole on the back of the alternator to the voltage regulator base and from there to the battery negative terminal.