it has a 350 with an edelbrock 4 barrel im not sure about ggear ratio on the truck but its a 2 wheel drive with a 3 speed automatic transmission, i drive on all types of terrain and i dont hot rod it around the timing is set accoriding to factory specs and im still getting 9 mpg no matter where i take it or how i drive it. this doesnt make sense to me. my friend has an almost identicle truck and he is getting 12 mpg