Better MPG?

[Houston-Longhorn]

Ok guys and gals, help me justify purchasing a '67 GMC 3/4 ton LWB Stepside that has a 305 that needs to be replaced. The truck needs total resto but I can get it for $600 or maybe less. But of course I need some rationalizations to help convince me that I need a project truck.

Since I will be replacing or rebuilding the 305 V-6 I was thinking I would install a FI engine and change the rear end gearing. If I were to do so, does anyone have any idea of what kind of MPG I might hope for. Any suggestions on gear ratio & cam?

The truck would be a weekend cruiser and backyard project hauler. I am not interested in the fastest 1/4 mile or pulling a 5k lb tow. Although a boat may be in the future.