Engines and Components› Crankshafts and Components

ASP Racing

25% Underdrive Crank Pulley Kit

$358.21

SKU: 948500

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Special Order
Ships in 4–6 weeks
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The ASP Racing 948500 is a 25% underdrive crank pulley kit designed for LS1 Camaro and Firebird models. This pulley system increases engine horsepower by reducing the power needed to drive accessories like the alternator, power steering pump, and water pump. By slowing these accessories, more horsepower is made available to the drive wheels, and the reduced rotating inertia allows for faster engine revving.
Show original supplier description
The ASP Racing 948500 is an SFI-approved underdrive crank pulley kit engineered for LS1 Camaro and Firebird models, with a 25% underdrive ratio for optimal performance. Underdrive pulley systems function by reducing the parasitic power losses from engine accessories such as the alternator, power steering pump, and water pump. Slowing these accessories down frees up additional horsepower for the drive wheels and also lessens the rotating inertia at the front of the crankshaft, contributing to quicker engine revs. This kit is designed to provide an estimated 9 horsepower gain, with a full charge at 900 RPM. When installing this pulley on an LS1 engine, a new GM crank bolt is required as the original is a torque-to-yield bolt that can only be safely used once. This new bolt is available as an optional add-on. Additionally, new belts are necessary for this kit, with the specified sizes being 760K6 for the accessory belt and 378K4 for the A/C belt. Gates belts in these correct sizes can also be purchased separately. The ASP Racing 948500 underdrive pulley is specifically designed for 1998-2002 LS1 Camaro and Firebird models. It is also compatible with the 2004-2006 GTO with the 5.7 LS1 engine.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

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Specifications

BrandASP Racing
Part Number948500
CategoryEngines and Components
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Shipping

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