* 3.7L V6: This was the base engine.
* 4.0L V6: This was available on certain models, like the V6 Premium.
* 4.6L V8: This was available on the GT model.
* 5.4L V8: This was available on the Shelby GT500.
Therefore, there's no single answer to your question; the engine size depended on the specific trim level of the 2010 Mustang.