Thanks, it's the 6.8. Does just fine. Coming across Kansas on I-70 in crazy wind, it was staying in 8th most of the time. Really like the motor, tons of low end torque. Love pushrod V8's. It's the 'Godzilla' 7.3 but with 6.8 liters of displacement due to a slightly shorter stroke. Also doesn't have a forged crank, and the trans is lighter duty. But I've driven both, and it's tough to tell the difference, after all, the 7.3 only has 25 more HP I believe and not much more torque either. Really sucks fuel though. Across Kansas in the wind I averaged 9. Best I saw with the camper was about 13. Unloaded it will get 15-16 at 75 mph. Also get way better mpg at home in Colorado than down at sea level in the thicker air.