Where is the choke on a 78 Chevy Caprice?

A 1978 Chevy Caprice doesn't have a choke in the traditional sense of a manually operated lever. Instead, it likely has an automatic choke. This means there's no visible choke lever under the dashboard or on the carburetor. The choke mechanism is fully automatic, controlled by a bimetallic spring inside the carburetor itself. You won't see it unless you remove the air cleaner and look at the carburetor.