and exhaust system restrictions, reworking the cylinder heads and replacing the camshaft with one possessed of more aggressive lobes.
   It's no secret that the C5's stock air filter offers significant resistance to flow. Aftermarket manufacturers have developed several alternative designs, and while many of these offer improved airflow capacity, some have reportedly caused low speed drivability problems. Construction is another consideration. Cottrell determined that an appropriate air filter for the C5 should demonstrate the same level of sophistication as the vehicle itself. Working with Donaldson Corporation (a major supplier of air filtration components to GM and other auto manufacturers) TPI Specialties developed the "Air Force 3" filter assembly. This unit incorporates a proprietary high efficiency, cleanable filter medium and an indicator that signals when the filter needs cleaning. The significance of this assembly is that it not only out-flows competitive units, it also offers superior filtration. Compared to a stock filter assembly, it allows an LS1 to crank out