[jagarra]

I am pretty sure I have a 3.54 rear end, I found a tag on the 3rd member cover indicating the ratio and that it was a posi rear end. All the hydraulics have been rebuilt, the brakes don't feel that they are dragging when I put the truck in neutral and coast to a stop light.
I do have the tuning book for the 2300 series Holley, I remember reading that if you lean a mixture too much that more fuel will be used to do the same work. I have a Summit warehouse in town so getting jets a just a short ride away, maybe I am going in the wrong direction with jets.
Since tomorrow is gonna be nice, before another storm, I will check the timing and pull a plug to get an idea on how they are burning.
As far as driving, it gets used just around town, going to dump transfer station, errands, and no major driving in the Sierras.
Fuel could be evaporating or my speedo could be off, too, like Ed said. I did notice that the needle is jumping a bit, indicating that cable needs lubrication. I still have the original carburetor and air cleaner, so I could put it back on, but it sure runs better with the Holley, the only thing I had to reroute was the choke cable since it comes in on the right side on the Holley.
Today when I was driving around I smelled gas, found a leak on the fuel line going to carburetor, fixed that so that may have contributed to poor mileage too, but it hasn't been driven much in the last 6 months, that only would leak when the motor was running anyway.