Renault 4 - this one specifically was made in Argentina
Well, altough it's not streamlined, its extremely light weight (600kg/1323lbs.) is a good point. The engine is mid-mounted, behind the front axle, which leads to a good weight balance. It was originally fitted with 4cyl engines around 0.75L to 1.1L. And in spite of its size it's actually not so cramped inside.