FAST 54103 102MM Big Mouth Aluminum Cable Driven Throttle Body - Chevrolet LSXDetails When it comes to improving your engines performance, increased airflow is a key ingredient. The FAST Big Mouth Throttle Bodies for the FAST LSX 92mm & LSXR 102mm Intake Manifolds increase airflow through a series of innovative design changes and a slightly enlarged throttle opening. FAST also invested significant testing & engineering resources into optimizing cross sectional flow and eliminating airflow turbulence, especially at part throttle