i have 2 rams a 02 1500 qcsb slt 4x4 4.7 i get what i call great avg 16to18 have hit 20 before not bad for 7.700lb truck now for the 03 2500 qcsb learme 4x4 5.7 hemie not so good if my son is behind the wheel 9 mpg if i drive it 13 mpg have hit 15 but i im talking about a heavy truck 8.300 lb and will pull what ever you need to pull i have even seen the duel wheel trucks pulling track hoes but i would say they was running the sweet cumming 350 now you talking about some pulling power