Starting with the recently released Holley(R) HP Series Carburetors, JET takes them to their maximum potential for the ultimate 4150 race carburetor. Venturi size is increased by .030 and throttle shafts are trimmed and radiused for the ultimate airflow from a standard flange carburetor. The metering blocks are fully blueprinted, balancing main well volumes, optimizing the emulsion system, idle circuit calibration, power valve circuit sizing and high speed calibration to precisely match the specifications of your motor. Delivering the ultimate fuel curve and fuel atomization for maximum horsepower and torque, plus unmatched throttle response and consistency. When you want the ultimate 4150 series carburetor for your pro street or race vehicle, the Jet Stage 4 HP is it.