I have a 200 amp large case alternator (previous stereo comp vehicle) with an adjustable external voltage regulator. I can set my voltage up to about 16v. I am not sure how our truck's electrical system would react to such high voltage, but a steady 14.4v is were I have had mine set for a number of years. No problems with the stock ecm or speed pro (currently using). Our fuel pumps run stronger with the higher voltage.
The max voltage of our alternators is set by the manufacture or rebuilder. You can have an alternator shop modify one for higher voltage output.
As long as the alternator has enough amps to cover the truck's draw your volts should stay stable at the set voltage. I am sure most of us turn everything off but the nessessary lights, etc when racing at WOT.
Our stock alternators are ok from an ampere standpoint at WOT with minimum draw (no extra load from stereo, fans,,etc., but the output voltage from the factory settings vary from truck to truck. I have seen some above 14v and others in the low 12s.
Also remember that putting an oversized pully on the alternator or an undersized pulley on the crank (for a small amount of hp) may cause a loss of voltage at lower rpms. IMO I don't think there is enough hp gain to offset for the voltage drop that our small amp stock alternator puts out. If you feel that there is something to gain by resizing the pullys and slowing down the alternator then get a higher amp alternator and an adjustable external regulator. Set it to 14.4v after you changed the pulleys.
FWIW I think sending the stock alternator to the shop and having it rewound to 140 amps (about max for a small case alternator if you want it to last) and have it set at 14.4v (or modified for an adjustable external regulator) is a smart mod.
John
