jbe, in response to your questions:
Thicker radiator cores will draw more amps, so keep that in mind. On top of that the 33A draw is especially bad at idle when the alternator isn't spinning that fast.
That information is not quite correct. A thicker radiator with reduce air flow in most cases. Affinity laws state that for centrifugal loads like a fan, theoretical hp is the square of the flow and the cube of the rpm. That means that the power requirement (including amps) goes down quite a bit when the flow is reduced.
In addition, when you are idling, the voltage drops. Again the power is a cube of the voltage, so when the voltage drops the current drops quite a bit. Flow also suffers quite a bit.
In my race car, I went from a 55 amp alt to 120 amp. Gong down the track I went from 11.8 volts to over 13. Clearly the alternator was too small. The higher voltage increased fan and water pump speed to the point that on a hot day back at the pits car was 20 to 30 degrees cooler than before - usually around 20 degrees.
