Bore size versus fuel mileage. 273 versus 5.2 magnum

My 273 gets almost 20 with a 833 and a 3.23 rear. It has plenty of torque. Mopar engines by design have torque probably because of the rod to stroke ratio. The Chevy guys always brag about building a 6" rod motor. Ya, my 273 has that and more. (Their jaw drops)