Original post by: Robert Cox ,
I've got a 2010 780 with the VED-13 set at 435 running the I-Shift and 3.21 gears. I run light grossing between 40-55 max, and also run out west. I have had no issues with the low HP. I usually only have to drop to 11th on almost any of the climbs, once in a while coming out of LA I'll drop to 10th. I only run at 56, so I'm at only 1200 rpm at 56, and it will auto shift at about 1050 so it may hold the gears better if your running faster to start with. I don't think you should have much of an issue with the 455HP engine. If everything is running correctly you should get good fuel mileage.