* Most common: A 5.0L (305 cubic inch) small-block V8 was the most prevalent engine. This was a relatively common and reliable engine for the time.
* Optional: A 5.7L (350 cubic inch) small-block V8 was available as a more powerful option.
It's impossible to know the *specific* engine in a particular 1986 Caprice Brougham without more information about that individual vehicle (like the VIN).