after running all three of the "mainstream" carbs for several years each - the holley makes, by far, the most power the Q jet makes least power and the edelbrock is the easiest to work on. the truck avenger is the best offroad-period! The deal w/ holleys is that they are very precise - when you tune them perfectly, they only run perfectly if the weather is what it was the day you tuned it! the other carbs are more vague in the tuning and therefore arent as sensitive to weather changes. just my .02 cents