67 Barracuda Heavy Electric Load

A typical charging system should be charging at 14.4v, so 12.4 is pretty low. Without the amperage of the fan motor, and the amperage of the alternator, it’s hard to tell whether the se components will live together. Looking at the alternator, it appears to be no more than a 48a-60a unit. A stock alternator for a 67 would be a 37a I believe. So, 48-60 is marginally better. I personally would not run a higher amp alternator without upgrading the charging system wiring, and either doing the amp meter bypass or running relays for the lights and fan.