What voltage should be on 130 amp alt.....

A bad power cable connection can make the gauge go crazy.

With no load and an otherwise full battery, something around 13.5 volts at idle is decent. If the alt(s) is/are running at max capacity at idle, the volts will likely go up at a given RPM (like 2000) because of the increased spin rate. But if the alt is not overwhelmed at idle, the volts should stay near the same.

Good luck.

Derek, I have no idea what the letters on the stock guage correlate to, so I cant comment on that part. Sorry bud.

13.5 volts at idle is pretty darn decent. I might like to see a little more, but not much.

Here is the thing: the alt charges the battery as much as the battery needs charging/replenishing (while accomodating the electrical draw at the time). If your just took your battery off the charger before starting it, the alt would be able to take it easy, needing only to break even, and then charge the battery back up from the cranking it had to do.
But if someone jump starts a dead battery (for instance), that is about the hardest thing one can do to an alternator - the alt will work at max trying to charge the battery. So just the state of the battery is important.

The key is that ~12.6 volts is break-even (with some gel cell batts, it is a little higher). Below that and you are discharging, above that and you are charging. And DON'T forget about voltage drops. Some voltmeters (in the car) read a volt or more less than what the voltage is at the battery. This can skew diagnostics.

With a non-topped-up battery, charge voltage can reach 14.5 volts or so. And yeah, normally volts go up with revs. Some of the newer aftermarket 3G's+, with an OD pulley and a car which has a higher than stock idle setting can put out decent volts right at idle.

This is where I bow out - I dont know about 2 alternator set-ups (is that what you were talking about in the first post?). If so, I would imagine that each alternator works easier (having to do 1/2 the work), so perhaps that is normal. I have no experience with it.

If Shane or one of the other gurus sees this thread, he/they will hook ya up with some real good info!

Good luck Derek.