As one of the Moderators here.....let me be the first to WELCOME YOU. 
283's can get very good mileage. I have one in my 1940 Ford.
Use a small 4V carb, good intake, good ignition (I use a MSD small HEI) and dual exhaust. A gear ratio of 3.0 to 3.25 also helps.
I had one in a 55 Chevy 150 sedan and got 20 miles per gallon real easy.