How many miles to the gallon on an 450 (7.4)GMC suburban?
Probably about 12 average.
Depends on your final drive ratio. I've seen mileage as low as 5 MPG to as high as 18 MPG. The higher the numbers the lower it's geared and the worse the fuel mileage but low end torque is great, the smaller the numbers the better the fuel mileage but the torque is reduced.
Search GMC Suburban Questions
GMC Suburban Experts
Related Models For Sale