I fully agree with Kalabin. 5.3L/3.42 with the 3.08 first gear compared to 6.0L/3.73 and 2.48 first gear and 750 pounds heavier HD won't feel like much better acceleration. Handling and suspension and stability will be improved.
And reminder, 6.0L/4-spd/3.73 tow ratings are near 8000 pounds, say 7500-8500. A 7000 pound dry bunk house TT will exceed that. IMHO, it isn't worth selling for what you got to "upgrade". You need to significantly increase wheel torque either through gearing or power. 6.0L/4.10/4-spd would be a marginal upgrade IMHO. 8.1L or Duramax both came with the Allison trans wich would be very noticeable. Or, 2007.5 6.0L/6-spd.
