I know I can tell the engine runs easier and less heat in tranny according to temp gage on hot summer day. I run a lower stall converter for pullin the mtns in wyo around 1600. hughes built up for me. didn't want a lot of stall. My ford is running on 40" hawgs and get around 9 to 10mpg on interstate. If running 38.5x11x16 boggers can get over 10mpg. I think this is good for a big truck. motor is solid cammed for lowend and midrange not really a high rpm situation just pullin mtns and huntin rig. Its a extreme huntin rig but it gets the job done. Pulled my dads new truck out again this year because the weather came in on us in mtns with rain/snow and sleet hail and whatever else mother nature could throw at us.