I once had a 1985 GMC S-Jimmy 4x4. Originally had a 2.8L (carb), 700R4 and got about 15 mpg because the motor was too weak to hold the truck in overdrive driving down the freeway. After swapping in a mild 350 V8 (4bbl carb) w/ 700R4 I started getting 18-20 mpg. So now I have a 1986 Chevy S10 2wd. It now has a tired 2.8L (TBI), 5 spd and 4.10 gears in the rear axle (according to option codes in glove box). I am now getting 22.5-24 mpg out of it and just started plotting... Anyone have an idea what kind of gas mileage a TBI 350 V8 would get in a 3000# truck if I keep the OD 5 spd?