Dancing Fingers wrote:
The thing of it is that the car they used, as I remember, also had a
very aerodynamic shape and it still helped.

Disagree - it was not "aerodynamic" on the downstream side.

Do you recall when they showed the wind tunnel and water tank tests? Do you
recall seeing that there was an area behind the car with turbulent air?
Well if the car had been elongated so that the body tapered off such that
it filled that area of turbulence, then I suspect they would have gotten
different results.

Check out the following site:

http://www.grc.nasa.gov/WWW/K-12/rocket/shaped.html

Notice that the prism has a slightly lower drag coefficient than the flat
plate. As that web site states "Comparing the flat plate and the prism, and
the sphere and the bullet, we see that the downstream shape can be modified
to reduce drag."