ThunderJet Adjustable Air Bleed Jet Pack with Jet Sizes: 140, 150, 165 & 175 Ajustable Air Bleed Pack for S&S 'E' Carburetors When installing a ThunderJet in any S&S carb, we recommend modifying the fixed-size main jet air bleed circuit to accept jets for additional tuning versatility. Air Bleed Kit includes 4 Jets for the most popular applications, this kit includes Jet sizes: 140, 150, 165 & 175 Instructions on how to perform this effective modification externally on the carb body for easy access are included with this kit.