good report on the 6.4.
I am watching for something similar to come along towing heavier, like a 11.5 to 12K plus fifth wheel.
I tow our fifth wheel thru the Smokies on I40 and then south on I 12. It weighs in at around 11.5. The only challenge is the Saluda Grade in NC heading north. It is long but sticks to 6%.
By any stretch, I am not wanting to do a high jack here. Mine just happens to be a 6.2 Ford.
Thanks for the info and I am looking for down the road info on what that big motor will really do when put to the larger test.