How much engine to tow 5500 lbs?

DougE wrote:
It sure didn't take long for the "Ya gotta have a big rig" guys to jump in. The PO is looking to travel the Midwest and New England so doesn't NEED anything so stout and expensive to run.

I had a 1999 F-150 that would have done fine for OP. I towed 6500 pound TT with a 2003 F-150 as well. But power and gearing in that era was far worse than today's trucks. A 2015 2.7L Ecoboost would probably eat up the 8.1L/V10 from 10 years ago. But OP isn't spending $40k+ on a new truck. Power from small blocks 15 years ago is adequate at best while towing with 3 usable gears. Towing fuel consumption is the same as more powerful gas options. OP noted 5000 miles per year, so not a weekender. There are hills in Michigan I that I needed second gear at 4500rpm for with my 5.4L. The V10 and 8.1L would provide a more pleasant towing experience. If the use case is more towing and not much highway unloaded, the overkill compromise is not important.

GM's 6.0L used the same amount of fuel as that era 5.3L. No reason not to get the extra 10% more power. The GM 5.7L was a dog. Dodge 5.7L is worth looking at, but I'm not sure what years to start trusting the trans, maybe 2004+.