What car is the Chevy 400 small block in?

The Chevy 400 small-block engine wasn't used in a single, specific car model. It was an engine option available across a range of Chevrolet vehicles, primarily in the 1970s and early 1980s. You'd find it in models like:

* Chevrolet full-size cars: Impalas, Caprices, Biscaynes, etc.

* Chevrolet trucks: Various C/K series pickups and vans.

* Some GM "A-body" cars: Though less common than in full-size vehicles.

It wasn't a standard engine in any one particular model, but rather an option available across multiple platforms.