What are your cam specs? If this thing is really lumpy, it will always be hard to get good fuel mileage.
Its a lot easier to get good fuel mileage when you have a carb with smaller primaries. Electric fans will help, especially if you don't have a clutch fan, but it's going to be a small incremental increase.
The most important things for fuel mileage are the timing and the cruise air/fuel ratio. Without having a wideband O2 sensor, it will be hard to get the air/fuel ratio right on.
With that being said, I have a 340 with a 750 Double Pumper Quick Fuel Annular carb and a 227/231 .530 lift cam and my car gets 12-13 mpg easily in the city if you keep your foot out of it (and have the ultra-progressive secondary link installed). Being hard on it, it gets 10.
Even with everything tuned in right, and quite a few tricks, its going to be hard to break 15 mpg. If I drove mine on the highway, it may just squeak into the 15's.