The air bleed under the air cleaner stud seems to have been an idea of Bill Jones. Barry Grant may have been the first to incorporate the 'idle-eze' into mass market Holley type carbs. They can be added to most 4 bbls. There is certainly debate about whether this is the 'best' way to bring in a little extra air. In its favor is the ability to make quick adjustments in either direction. It also can be used regardless of secondary systems.
