My 2006 Duramax has a nice unoccupied space in the engine compartment specifically for a second alternator. It even has mounting lugs to just bolt on a second alternator quick and easy. I don't know if there was ever a factory option to have a second alternator installed. The reserved alternator space and lugs might be there for heavy duty applications like a Kodiak?
I would love to put a second alternator in there... only I have absolutely NO need for a second alternator. The stock alternator has always provided plenty of power and has always charged my trailer without a problem. Sounds cool to say you have two alternators though!
