If I remember correctly, the jumpers only affect how soon your fueling rate increases so that you can keep smoke under control, especially if you have bigger sticks installed. On setting 3, you'll get hard fueling at very low manifold pressures, while on setting 1 the fuel does not start coming on very hard until the manifold pressure starts to come up, more like stock. Setting 2 is somewhere in the middle. Changing the jumpers will not affect your total power output though, if your EZ gave you an additional 40 HP, you will get that additional horsepower regardless of which position the jumper is in. To return to bone stock, you would need to remove the box.