The QJets are very good carbs for fuel economy. First the Carter was phased out, then they Holley, then the QJet. There is a reason they were phased out in that order. The Carter got the worst milage and had the worst emissions while the QJet had the best milage and lowest emissions. They are the closest thing to mechanical fuel injection in terms of carbs. Their primaries are tiny which makes them excellent for cruising, but they can still flow 750 cfm which gives them good power, too. The power doesn't come on smooth like a Holley which makes them no good for racing when traction is an issue, but it can make all of the torque and hp of a lower end Holley on a street motor.