Performer Series carbs are made from a high-quality 2-piece aluminum casting that has no gaskets below the fuel level so you can change jets, rods, adjust floats, replace needles and seats without having to drain fuel or remove the carb. Available in 500, 600, 750, 800 cfm sizes with manual or electric chokes, they have no power valves to fail and the secondary air velocity valve senses airflow for a smooth transition from part to full throttle. All Edelbrock carbs are user-friendly and will ''hold-a-tune'' for thousands of miles of reliable performance.