Car Stereo/Alternator Question Please help!!?

Okay, So I have a 1996 Ford Explorer with a 4.0 Liter V6 Engine, and I'm pretty sure the alternator in it ((stock)) is 135 Amps. I am not running many other things in the explorer, other than 3 stereo amplifiers and a 2 Farad Capacitor. I have a 400 Watt 4 Channel amp with a 15 Amp fuse, a 600 Watt 2 channel amp with a 20 Amp fuse, and a "2600" watt amp with 2-25 Amp fuses. So the total fusage all together is 85 Amps. Now is that too bad for my stock alternator? Could I add another 2 channel amp? What's my limit here for amps until I end up frying the alternator??