The BlackJack Carburetor is a high-flow performance carburetor designed to be user friendly utilizing a proven annular discharge design with modified internal circuits. It consistently offers instant throttle response without loading up, even after prolonged periods of idling. The BlackJack Carburetor incorporates a flow bench designed, CNC machined billet air velocity stack with a true venturi providing more precise high speed transition. There is no booster venturi or protruding nozzle tube to restrict flow. (Tests have shown the addition of a nozzle tube will decrease flow by as much as 9%)