The Holley 1904 is a 1 barrel, downdraft carburetor and has three basic parts, the main body, throttle body and the float bowl. The main body includes the metering block, float and the economizer. The float bowl mounts on the front of the carburetor and can be metal, or glass. The glass bowl is becoming a rare piece to find, undoubtedly because they are so easy to break and they are not made any more.
Having the float bowl on the front allowed the 1904 carburetor to be designed with a low profile, which accommodated a smaller space between the engine and the hood. While we are fortunate to have carburetor kit coverage for all of the 1904 carburetor numbers, there are few other parts still available. In particular the float and the plastic actuator are very rare these days. We get quite a few requests for these parts, but when we do find these parts, they generally go on other 1904 carburetors. Your best bet to obtain these parts is to find a used carburetor and use it for a parts donor.
When you can’t find the carburetor number on the Holley 1904, it may come down to measuring the accelerator pump diaphragm to determine which carburetor kit to use.
Watch this video on how to measure the pump.
Look for your carburetor number on the pad just left of the float bowl. Example: cdte 9510 A. In this case cdte is what you are looking for. Add the A as in cdte-a. Some will have the LIST number, may a say LIST 1911 1 This would make it LIST 1911-1