How much power will he be running? I currently run stock alt, 2 runs 00awg and 2 xs power xp3000's. on a sundown 2500 and no drop. ask me anything. And for the dual alt good luck with placement. you would have to kill power steering or ac to get it to fit. Ive never seen it done so most liky will need custom fab, not to mention the pcm controlling them