New ISX motor ?

[Chamberpains]

If you're keeping your working RPM above 1300 and not lugging it, with your OTR operations and driving it easy you're not hurting it at all. I wouldn't change ratio's (not worth the expense without cause) unless you start living and pulling in the mountain regions all the time or its time to change a rear. Then I would put both in at the same time and up your ratio.

Your gears aren't ideal but I think you can keep the RPMs up. You just have to work harder at it. It's when you get those dumb 3.27 and below ratio's when they can't keep their working RPMs up because of how long that gear ratio is. Any time a bug farts those guys have to drop gears.