4barrel for 327

A four barrel can be economical. It's basically like running a pair of two barrels, but you only run on two all the time, the second two only as needed. A small 4V works great for a typical street application as the small venturi keep charge velocity up, which helps with the mix and improves torque a bit. At some point in the rpm range the carb, even with all four open, will become the limiting factor, so for high performance operation you want a larger one. Typically something that performs well up to about 5000 rpm is all you need/want for a street or even mild street/strip car. My Jeep J-10 with a 258 and 390 4V was very economical, averaged near 20 mpg as long as you kept speed down to about 60 mph. Start going much over that and air resistance increases power demand (start stepping into the other two barrels!) and severely decreases economy. It would cruise at 80 mph easily -- and get about 10 mpg doing it. It had a manual four speed trans with 2.73 gears... 4th was about like OD and you had to slip the clutch a bit in first even on a normal take-off with a light load. Of course if you needed it there was always low range...