When it comes to improving your engine's performance, increased airflow is a key ingredient. The FAST Big Mouth Throttle Bodies for the FAST LSXR and the LSXRT102mm Intake Manifolds increase airflow through a series of innovative design changes and a slightly enlarged throttle opening. FAST also invested significant testing and engineering resources into optimizing cross-sectional flow and eliminating airflow turbulence, especially at part throttle operation.