Where is the 8 cylinder on a 2005 Lincoln ls?

The 2005 Lincoln LS offered two engine options: a 3.0L V6 and a 3.9L V8. There is no 8-cylinder engine in the sense of a straight-8. If you're referring to the V8, it's located in the front of the vehicle, under the hood, in the engine bay. Like most front-engine vehicles, it's positioned longitudinally (lengthwise).