KD4UPL,
Thanks for the reply.
Sorry, I should have been a bit more clear in the first instance. My current truck is ten years old and is rated at 403 hp and 417 lb/ft. Which is why I was curious if the added lb/ft in the 6.6L would resolve the question I posed, or if it would benefit from a higher hp, more than the increase in torque.
As mentioned, my truck pulls fine for most applications, it's just when we are out on the interstates and extremely long distances that I wish for a wee bit better performance.
Marv