I've found a 1993, 1995, 1996, and a 1997 Chevrolet Suburban with 7.4L or 454 ci V8s around my area and I was just wondering what type of fuel economy these guys get with 4x4? Estimates would be fine. Just curious. Well, thanks.

At best you will get 10 miles per gallon on the highway and that is most likely going to be with the wind behind you and going down hill. You don't get a Big block for fuel mileage you get a big block for just pure raw torque.
If you want better mileage and need the power for pulling get a diesel. If you do not do much towing then get a small block.