I'm on the far east side in Sidney. I go thu Missoula a fair amount, but seldom make it to your area. If i was gonna keep the truck, I would consider doing the 6.4, but It's a flipper. I looked a little closer at the newer motor, and only thing I notice is the coolant cooler between the oil pump and filter. The dealer here has one of the "Noisy" 6.4 takeout engines that I've been trying to get. That would go into my backup towing rig. Hard to beat my '05 Cummins for towing, tho. Jim