Taking some cues from racers and street heroes alike, Holley has taken their own Model 4150 carbs to the next level with the new Model 4150 HPs. Updates include cast main bodies without choke horns, and smoothed venturi transitions for increased airflow. Since they're aimed directly at optimizing power and performance for racing applications, other important modifications include screw-in air bleeds, stainless steel throttle plates, notched floats. They also have Dominator style fuel bowls to allow fuel line plumbing from either side.