[dwaite72lnghrn]

Rebuild the qjet or buy a rebuilt unit. If fuel economy is your goal do not put a square bore carb on it. I think part of your problem might be the choke is never coming off with a short run like that. Add a vacuum gauge to the truck and when you run down the road try and keep the highest vacuum on the gauge possible. My truck runs about 20" of vacuum running down the road at cruise speed when I am in town it is about 12" or less and my fuel mileage drops off quick. If you are running stop lights the whole drive to and from 8mpg might be all you can get out of it.
If I run with a light gas peddle and keep the rpms at 2500 I can get about 13.5-14mpg. That is with the c30 longhorn that weighs 5300lbs and 4.10 gears and a turbo400.