Formula 1 car without regulations

Okay, one thing in advance – I’m not an F1 expert. But every time I read about all the regulations regarding the cars, I wonder what a Formula 1 car would look like that wouldn’t be subject to any regulation at all…what would it look like? What kind of engine would it have? Nen 2 liters turbo with 2000 hp or something? What would the car look like on the outside? How wide would you make the car? I know, it’s a far from reality spinning, would still interest me…