These main venturis (choke tubes) fit the Weber 40 DCOE carburetor. They will also fit the less-common 38 and 42 DCOE. Two are required per carburetor. Sold individually.
What size do I need?
The venturi size is the first step (after choosing the carburetor) in tuning a Weber carburetor to your application. It is tempting to use the largest size for the most airflow, but this can hurt performance. Too much airflow impairs low-end driveability. In fact, the car may not start or idle at all. And remember that the engine has a limit to how much air it can use. Feeding it more will not produce more power.
The book Weber Carburetors by Pat Braden (Part No. 5326) includes venturi selection charts based on engine capacity, use, and RPM.
Weber part number 72302, replaces Weber 72303 and 72304.
