The Holley model 2140 and 4000 are 4 barrel downdraft carburetors, called 'concentric' models by Holley. These are sometimes referred to as 'Teapots' because they consist of a throttle body assembly with a float bowl suspended above.
Famously, model 4000 carbs were used on the Thunderbird V-8s from 1955-1957, including the dual carb 1957 312. TBirds and other Fords with the Teapot carb from 1955-1957 used kit CK7010
Before the T-Bird, the first four barrel Teapot, and in fact the first four barrel Holley, was the model 2140 used on 1953-1954 Lincolns and Mercurys with the Lincoln engine. These take our kit CK7013
Governed models (2140G and 4000G) were used on various heavy-duty truck applications, including IHC trucks into the 1970's. The IHC trucks use kit CK7311, as well as other makes. Fords, GMC and REO used mainly kit CK7312. More information on applications is on the respective vehicle catalog page.
How to find carburetor numbers
Carburetor numbers were stamped on the rear of the base of the carbs, as well as appearing on tags.