Why run dual quads?

The dual quads on my 318 were hooked 1 to 1. The car starts, idles and runs unbelievably well whether cruising around town, going down a highway, or smashing it to the floor. I don't know what the exact gas mileage difference was because I didn't check, but by the gage really no big difference that I could see.
However, they are being removed because of a specific project with the car, no other reason.