ISX450.......unrealistic expectations?

[Golfnut]

Chamberpains.....I appreciate your honesty and your right on some things and wrong on some others. I've maybe made it sound like I want to run fast all the time. That is not true as the majority of my hauls will be short hauls to the elevator and back. My concern is that my truck flat out acts like it does not have the ability to go any faster than 63-65 on flat ground. Zero top end power. I don't want to be stuck at 63 mph because that's all I've got. I'll be getting poor mileage regardless of my tune because my trips will include too many turns and stops. An average run to the elevator for me is 8 miles with three stops/turns plus one railroad crossing.

For the record, I'm not looking to run 550/2250. I realize that would be overkill. I'm sure there are a few of those around but not many. I'm just trying to learn what I've got./