Took it to the NHRA Hot Rod Reunion in Bowling Green, KY. It was freakin' hot!
Oh yeah, it looks like I finally figured out why the truck was getting crappy gas mileage. The big chrome fuel pump was pushing gas past the needle and seat. I put a stock fuel pump on the truck and my gas mileage jumped from around 8 mpg to 15!
I don't think I will get much more out of it with 20's and the overall aerodynamics of this truck.
...over 5,500 miles on the truck.