Edlebrock performer carbs are good. I have a 500 CFM one and my old 2 barrel was not very good but had heaps of low end but I think with the new intake manifold and carb from Edelbrock, the performer series, I am getting better MPG. They come already tuned for your application but I still messed with the idle mixture screws and timing on the motor a bit too and got it running a little better. I still need to fine tune it but I don't know exactly what to do with it or how I know I have the best tune so need to find some local guy to help me out. Edelbrock stuff IMO is more for street motors and a good choice for an everyday driver. Holley is good too but from what I hear they are better for strip cars and for people not caring for gas milage and just performance.