I test drove the truck, it's probably got a lot of torque hiding in that motor somewhere but when you mash the skinny pedal it doesn't inspire. My truck is running a 5 star tune (87 performance tow), and I believe the v10 also would benefit from the same treatment. My truck was pretty tame before it was tuned as well.

^^^Thats kinda what I meant when I said it feels like a pig empty. You anticipate it to feel even more sluggish when you hook up a 5 ton trailer to it, but then it fools you and makes it feel like there's no load on it at all. It's all relative.

Honestly the trucks will probably tow very comparably. So it would be foolish to step back a generation in trucks, as the other guy said. I'm surprised you're not over your payload capacity though with 5 passengers, firewood, + tongue weight of 6k lb trailer?

What about getting 4.10s or 4.56s for your truck? Did you know you would be towing in the mountains when you chose the 5.0?

I'm right at payload hooked up and ready to camp, maybe even a hundred or so pounds over. I had a tent trailer when I bought my truck, then moved up to a hybrid, then to a full on hard side trailer. So 3500 pounds of trailer went to 4500 and now 6200 all with the same truck. No trouble pulling my previous trailers. Payload is a stinker though, can't bring my ATV camping ever just for payload issues, let alone the added weight when I'm already up pulling heavy in the mountains. 6k pounds should be nothing for a super duty even with an ATV in the bed, even if it has to spin the motor up to climb hills. The cooling capacity is better for sure and I believe low rpm torque of a large displacement motor will help. But the underwhelming feeling of power on the test drive kept me from working a deal right there and then.

It's still a Lariat, has backup camera and sensors, leather, sync, two tone paint, power scope tow mirrors, etc so I'm only giving up a gear in the transmission but I lock out 5 and 6 when I tow anyway and only get 9mpg with the 5.0 which is not my daily driver.

5* has a great reputation for tuning the V10. You may want to discuss with them.