I run a stock 250 engine, stock T350 automatic with stock inline six converter, 3.08 rear axle from a Firebird with 235/75R15 radials ( 28" tall ). The truck weighs 3580 with two people and full of fuel. Mine is a '37 so not very aerodynamic, but it will run 70 mph all day long and still get 20 mpg. I can keep up with traffic in town or on the road. It will chirp the tires form a standing stop and has plenty of pull. I have pulled a small trailer filled with heavy antique single cylinder engines without any problem. I used to have a 3.42 gear ratio, the 3.08 is much better.
