I've got a 96 Ford Thunderbird with the 4.6L and I think it makes the perfect sleeper. No one ever seems to think it is as fast as it is and I love the look on the faces of the people when I blow by them. You can use pretty much any of the engine ...
The old unsuspecting cars that creep on you at a red light that are old, rust buckets, and granny cars that make you eat their dust when it turns green and leaves you feeling embarassed in your mustang, camaro, firebird, or whatever.