The Edelbrock supercharger Stage 1 Street system part #1577 is for 2003-06 Silverado and Sierra 1500 and 2007 Sierra Classic vehicles. This supercharger system works with the 6.0L 4.8L and 5.3L Gen III engines and increases the performance of the 6.0L engine to 348 horsepower and 381 ft-lbs at the rear wheels 4.8L engine to 339 horsepower and 359 ft-lbs of torque at the rear wheels and the 5.3L engine to 345 horsepower and 381 ft-lbs of torque at the rear wheels. The core of this system is the Eaton Gen VI 2300 TVS rotating assembly with a four-lobe design with 160 degrees of twist for maximum flow minimum temperature rise and quiet operation for excellent drivability. We also designed our superchargers with an integrated bypass valve to help eliminate parasitic loss under light throttle improving mileage potential. Our unique and efficient inlet configuration results in a shorter less restrictive intake path for improved airflow without the need for a jack-shaft. Keeping the air cool is a high-capacity air-to-water intercooler and low-temp heat exchanger. The Edelbrock #1577 system is 50-state emissions legal. The supplied tune is intended for completely stock vehicles with the exception of a cat-back exhaust.