67 Barracuda Heavy Electric Load

So my 67 barracuda has an electric radiator fan and I have noticed that the car wants to die after about an hour of driving then coming to a stop light when driving at night. Wondering if the extra electrical load is too much for extensive driving. There is a high output Mopar alternator on the car now. It seems like even a standard alternator should keep up. Last night I drove for about an hour with lights and wipers on and electrical radiator fan running. Usually I have a trickle charger on the battery before driving but did not this time. When I got back home the car would die when I stopped it at an idle. Usually it starts right back up but this time it would not even turn over. I charged it up for about an hour and it started right up again so I could get it back into the garage.

Do I need a voltage regulator that allows more amperage to pass through during normal operation?