Even a Dodge or a GM with the V8 options would tow a 7-8,000 lbs trailer in a 15 series fine. I would bet a 2014 or newer GM with the 4.3 and 6 sp trans would work too. As that motor has an additional 100 ponies and 50-80 lb ft of torque! Not to mention the two more gears!
With that said, The eco boost ford gas motor would be the BEST option for elevation, as the super charger keeps the sea level HP up to around 6000-8000' minimum, before starting lose HP to elevation. The dodge diesel would also be another option if you are at 5000+ feet of elevation a lot of the time.
ANY truck built in the last 5-10 years will be better than than one you have now! I've towed with that V6, its not bad, when under 5000, but the one you got, I would want the newest version, or something newer than the 07 ford too!
Marty
