Increase horsepower and torque with a new pulley that increases the boost from your Cobra’s supercharger. These Supercharger Pulleys are made from steel for long term durability and have holes drilled around the center of the pulley to lower the rotational weight. This is the highest quality pulley available for the 2003 Cobra. 3.10" pulley produces 1-2psi over stock. Testing has shown 25+ horsepower. Electronic engine tuning recommended to give the processor the ability to compensate for the added boost. 2.81" pulley produces 4-5psi over stock. Testing has shown gains of 60+ horsepower. Requires electronic engine tuning (Chip, Predator or SCT custom tune) and a shorter belt, Gates part number K080740 (not included) Cobra and Lightning supercharger pulleys are pressed on, and require tool # 555-8900 for installation. We can also install them for you in our shop. Eatonpulley$83.95 Pulley Size: 2.81 inch3.10 inch www.realspeedauto.com Ph.631-563-7325 All parts listed are for the Ford Mustang unless otherwise noted. Copyright 2018 Realspeed Automotive Inc. All rights reserved.