The Edelbrock E-Force Supercharger Stage 1 Street system part # 1577 for 2003-06 Silverado and Sierra 1500 and 2007 Sierra Classic increases the performance of your 6.0L Gen III engine to 348 horsepower and 381 ft/lbs. of torque at the rear wheels. The Edelbrock #1577 Supercharger also works with the 4.8L & 5.3L Gen III engines, HP & Torque numbers will vary. The core of this system is the Eaton Gen VI 2300 TVS Supercharger 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 air flow, 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 emissions legal and provide the best combination for your daily driver when used with Edelbrock tune. The #1577 system increases the performance of your 4.8L Gen III engine to 339 horsepower and 359 ft/lbs. of torque and for the 5.3L Gen III engine increases to 345 horsepower and 381 ft/lbs. of torque at the rear wheels.