Seems honest, should help the OP.I used to have a 2000 half ton with the 318 (5.2L) then my trans decided to burn out. I bought another 00 half ton that was in a nasty rear end collision for cheap. This one had the 360 (5.9L). I swapped the engine and trans. As far a fuel mileage for me it was roughly the same with no load on the highway at 75 mph getting around 12 mpg on a good day. The only noticeable difference was when pulling a load. The 360 has more torque and just a little more HP. There is more of a difference between torque from the 318 to the 360 but the HP is only about a 5 HP difference. Hope this helps.