Dynamic Cubic Inch

gas mileage is driven by where your foot is.If you driven a 273 to the boards all the time,the gas mileage is crap,if you drive a 360 using a feather the mileage is greater than the 273.If every thing is equal,the 273 should get better mileage,in theory.If you built a 273 the wrong way,it runs like crap,the opposite is true for the 360,built and tuned for max mileage,it out beats the 273,so where do you want to draw the line,mrmopartech