360 driver build

Haha well I also gotta keep mileage in mind. I'm hopin to keep my dart as a daily driver for quite some time. N I'm Talkin ballpark 20mpg. Meaning 18-23 is wut I'm aimin for. I'd love 300hp if not more but well see. I'm lookin into dougs headers and true duals all the way back. Idk jack bout x and h pipes. I heard a 4 br thermoquad carb will keep the hp/mileage decent but I really kno nothing haha just a kid