Unorthodox Racing PS10161 Power Steering Pulley - 87-89Unorthodox Racing Ultra Accessory pulleys are included in our Ultra Street Sets or may be purchased separately. They are CNC-machined from light weight 6061-T6 aluminum billet. As with all Unorthodox Racing products, tolerances for each accessory pulley is held to within .001". In addition, numerous machining steps are taken to ensure the pulleys are the lightest possible design. Premium fit and finish ensures a beautifully matched set you are proud to display under the hood of your vehicle. Power gains through the use of Ultra Accessory pulleys are obtained through weight loss (15% to 30%). Unorthodox Racing does not underdrive with the accessory pulleys (most applications) for two reasons. The main reason is because all underdriving is done with the Ultra Street crank pulleys. This provides maximum weight loss at the crank where most of the horsepower gains are found. Second, not much horsepower is gained from extreme underdriving. It is important to keep charging systems, air conditioning, power steering, and water pumps moving fast enough for every day driving. Since Unorthodox Racing Ultra Accessory pulleys are the same diameter as the stock units, you may install an Ultra Street lightened underdrive crank pulley as a first step. Then, at a later date, you may purchase the Ultra Accessories and install them without having to change belts again (on most models, otherwise the belt part number is included in the instructions). For 87-89 only.