Audi Sport Quattro, a giant turbo with a small 5 cylinder engine bolted to it
http://www.youtube.com/watch?v=hEK7P...eature=related
Or how about the old BRM H16 (two V8's on top of each other) F1 engine from the late 60's? Supercharged 1500cc (yes 1.5 litres!) with over 600bhp
http://youtube.com/watch?v=Tk8qPlOKB0I