ASP's 25% underdrive crank pulleys for the 5.7L LS1 F-body & Corvette and 5.3L GM Trucks incorporate a new harmonic balancer in their design. It is required that you change both the AC and the Accessory belts when you upgrade to this pulley.

The ATI Serpentine Super Damper contains grooves for serpentine belts machined into the outer damper shell. The dampers come standard with 6 outer grooves for standard OEM drive systems. 8 & 10 grooves are availabe for supercharger or turbo applications. The Serpentine Series dampers fit all ATI GM-front crank hubs and can be adapted to many engine combinations providing maximum flexibility. The dampers are available in steel or lightweight hard-coated aluminum and come with laser engraved 360-degree timing marks. Exceeds SFI 18.1 specs. *LS1 Crank Pin Drill Fixture Kit The ATI Crank Pin Drill Fixture Kit for the LS1 Super Damper allows you to install 1 or 2 dowel pins to the LS1 crank, eliminating the damper twist on the shaft. This is a must for circle track or forced induction engines.

Use Katech's billet adjustable belt tensioner to eliminate belt resonance commonly experienced from the LS1 engines, especially when using ATI dampers. This tensioner is a direct replacement for the factory piece, but adds the flexibility of adjustment to compensate for variances in the accessory drive system.