Install a wellrebuilt 105 amp premium alternator with a standard6-groove pulley, a new orgood used belt tensioner and a good size 75 or78 battery. A premium 105 amp alternator and a AC Delco 78-60 batterywhichhas710 cold cranking ampswith 78 amp reserve capacity is more than enoughpower for boom boxes and as manyelecronic accessories that a person could put on a vehicle. A functioningbelt tensioner is essential to prevent belt slippage that will result in low voltage output from the alternator.

I have not yet figured out whata "high performance alternator" is. The alternators used on the 370 HP to450 HP high performance cars from 1962 through 1970 wereusually 47 amp alternators with 6" diameter deep groove pulley that reducedthe alternater speed. If someone must put a smaller pulley on an alternator in order to increase the voltage output, there is definately something wrong with the alternator.

 

I have a delco CS144 alt that pumps out 145 amps (factory part on many large GM cars), a Deka group 78 hybrid battery with 850CCA. My at idle amps on this alt is 100. I pulled it from a junk yard but can be had easily at any parts store.


A high performace alt has nothing to do with the car it was on. Just like you can build a 350 to be high performace and drop it in a pinto. The alt is just built to put out more than it came from the factory. The smaller pulley stemed from guys that needed the higher amps at lower RPMs. Its a fine fix if your not gonna spin the alt faster than designed but its gotten to the point when this is a cure all and guys never take into fact that while they are going down the road they might be over spinning the alt causing it to fail faster.

If you wanna know how slow/fast your gonna turn your alt with X inch pulley here:

crank pulley in inches / alt pulley in inches = _______ X lowest motor RPM = _____ Lowest Alt RPM

crank pulley in inches / alt pulley in inches = _______ X highest motor RPM = _____ highest Alt RPM

You might be suprised how fast just a 2 inch pulley spins a alt.