Alternator Sizing - Amp requirements

Remember that 90 amps is the max output. For street use, the output at idle is at least as important. That 90 amp alt may only put out 50-60 amps at idle speed...
I used a CS-130 alternator that's good for 105 amps... also electronic ignition, Holley electric pump, Ford Contour elec fans. Keeps up fine, I can't find the test sheet with the amps vs. rpm curve though - but since my idle speed is 1200 rpm it seems to be turning the alt fast enough :)