BETWEEN THE 3 MOTOR SIZES, WHICH ONE GIVES THE BETTER FUEL ECONOMY

hi Terry, Unfortunately there are no official numbers on fuel economy for the 2008 F450 Super-duty. The Ford site doesn't even have it listed. My guess would be if you are looking for the best fuel economy then you would want to look at the 5.4L V8 or the 6.4L Turbo diesel. Keep an eye on fueleconomy.gov for official numbers on fuel economy.

for fuel economy best to go with the 5.4 L gas for the ford

terry if i was you i put that many miles on it i would get the 6.4l diesel and a six speed, but if you want a six speed i would hurry cause word on the street is for is going to drop the manual transmission.

hi terry every day of the week diesel will be more fuel efficient than gas simply because they redline at what 2800 rpm diesel with a six speed is diffinatly the way to go but the auto's are also good on fuel if you are putting 75000 a year on it expect a new gas truck every 3-5 years, diesel will last longer but be prepared to spend more money maintaining it the oil is more expensive you have more filters ect. the 08 line of truck are also a beautiful ride they are alot quiter than traditional diesels and the twin turbo gives them alot of power, also with a diesel the fuel economy doesn't change from regular driving or pulling a load dodge has the best economy but the front ends are weak chevs and ford are roughly the same of you are doing off road work ford is the leader