Specifically, it's a valve that's controlled by the engine computer (ECM). The computer opens and closes the valve based on engine load and speed to regulate the amount of exhaust gas that's recirculated. You'll find it somewhere in the intake manifold area, likely near the throttle body, but its exact location might vary slightly depending on the specific engine (the Caprice Classic came with a few different V8 options). It will probably be a small, usually metallic, valve with a vacuum line connected to it. A visual inspection near the intake manifold should reveal it.
