Should I put alternator pulley back on?

[Chris_H]

Wed. is the tenative date for installing my Stewart water pump and my Black Magic electric fan. I have underdrive pullies on the car with the stock alternator. Should I go ahead and put my stock pulley back on, or do you think this 65(?)amp alternator with and underdrive on it will be enough to run the car, fan, and a/c? It doesn't dip down too low on the volts right now, but at night I can see my headlights dim at a stoplight. I just don't need a dead battery one day. Any suggestions are more than welcome.

Chris

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1987 LX, rebuilt 306, Mac shorty headers 1 5/8, 2 1/2" Mac off road h-pipe, 2 1/2" 2 Chamber Flowmasters cat-back, Mac underdrive pullies, 3.55, K&N, Tremec 3550, King Cobra Clutch, Steeda Tri-Ax, Autometer gauges, White face gauges, blue silicone radiator hoses, Steeda Clutch Adjuster Kit.
Best times:
2.331 60ft, 9.966 @ 71.069 1/8 mile, 15.491 @ 91.846 1/4 mile at 4000 ft. elevation on street tires