If you ask anybody, really anybody, doesn't matter how young, old, short, tall, fat, thin, rich, or poor, what the prototypical "big engine, small car" vehicle is, they'll tell you it's the Shelby Cobra. It's one part little tiny AC Ace roadster, and two parts ridiculous big V8. As it should be.
Genuine Shelby Cobras go for stratospheric prices today, and for good reason. Not only are they a hoot to drive, but they capture an iconic look as well. That gaping open mouth can really only mean one thing, and that's silly amounts of power. The 289-engined Cobra is generally regarded as the more balanced of the two models originally offered, and though its power claim of around 270 horses might not sound like a lot today, it's plenty when your whole car is basically just four tires and an engine.
The 427-engined Cobra, on the other hand, was a hairy monster, with somewhere north of 400 horses. Of course, a lot of engines were underrated, because it was the 1960s and people were just nuts then. I mean, people were voting for LBJ left and right, and he was the kind of guy who liked to pee on people. Literally.