2011 Avalanche White Xterra Pro-4X
Join Date: Feb 2014
Location: Orem, UT
I did a 600 mile round trip pulling a pair of heavy Sea Doos earlier this summer, though significantly lighter than what you are talking about, and tongue weight is pretty low, so minimal sag with my DAAL + shackles. I filled up with 91 and loaded the high-octane tune into my BullyDog (normally do regular tune, +2 timing, and WOT restrict off). I think the tune helped some, plus I have an IMS, so the truck hardly struggled. But the trip did make me think more seriously about regearing from my AT 3.36 w/285s.
So in summary, a BD does help some, but regearing may be the better thing in the long run.