The Big Gulp is recommended for a 102mm, 103 mm throttle body or larger for optimum performance. This sleeve is designed to be used with a throttle body of 3.850 inch to 4 inch throttle body clamping surface.

The sleeve installs directly on the throttle body and acts as a spacer for clamping the big gulp coupler.

Installation Instructions - https://www.asapnetwork.org/sites/default/files/rfb/installation/10212047_Camaro_TB_sleeve_install_PDF_0.pdf