What is the other box upstream of the large heat sink? I assumed it was
a controller / regulator. Looks like it goes in the dash / panel. Also
they make several current ranges. (Can't find them on the new site) But
I know I read about a 22A and 32A unit in the past. Not sure if it is
possible on the shaft but John did say they where stackable on the water
pump unit. Would that require two belts

Bobby,

 I think there is something being missed here. On the permanent magnet motorcycle alternators they prevent over voltage by ungrounding the Y winding on the alternator preventing power from being produced. You can also size the coils such that they begin to internally quench themselves at a certain RPM but that is dangerous since they can fail. The point here is getting an alternator that DOESN'T HAVE A BELT at all. (e-shaft pulley) That is super even if the alternator is otherwise totally conventional. IMHO

Bill Jepson