What would vintage cars look like tested in a wind tunnel?

Vintage cars as in: those early 1920's-1940's boxy-shaped cars like the Ford V8 Flathead engines, and also the cars of the 1950's when aerodynamics and curved designs first came out.

Added (1). My question is asking about how the fog in a wind tunnel would appear, how much drag there's, or if earliest metal-roofed cars just scattered the wind (back when the tires had spokes that was assembled kind of like on bicycle wheels.

Added (2). ).

The aerodynamics of a lot of vintage cars were slightly better than that of a brick wall. Vehicles from the 30's and 40's with the sloped rear ends were actually more aerodynamic in reverse compared to going forward. Not that it really mattered very much as early vehicles did not have very high top speeds.

For years engineers knew the importance of aerodynamics for fuel economy and high speed stability.
Aerodynamic design was incorporated into racing and limited production vehicles but it wasn't until the early 80's or so with vehicles such as the Audi 5000 and the Ford Taurus that aerodynamics played an important element in design of mass production vehicles. Sure, there were earlier attempts such as the 1931 Chrysler Airflow but it did not catch on with car-buying public and was considered a sales flop.

Hi the difference is in the speeds they could manage back then when compared to speeds these days. Wind tunnel is for air craft body shape tests. Some modern super cars can now reach 300MPH

Until the fuel economy standards in the 1980s there was not much incentive to produce aerodynamic cars. Even today there's a large body of resistance among some car buyers to aerodynamic styling.

That is not to say it was always ignored. The 1934 Tatra T77 - first source - boasted a remarkable coefficient of drag around .21.

1920's-1940's did not have flathead V8 engines. They may have gotten to the in line 6 by 1940 but not too many cars had that. Mostly 4 cylinder motors. Then WW2 halted production of cars 1942-1945
. So speed was not a big thing in a car that could cruise at 25MPH down a dirt road full of potholes… And ruts.
Cars were still horse drawn carriages without the horse. So boxy was the style as it is more roomier inside for the people to sit upright… And be seen… Still wearing their TOP-HATS and Petticoats.
They never drove out on windy days because the car would go nowhere fast if it was a headwind; and really fast if it was a Tail wind.

They were not as boxy as they were in 1920 as the design was changing. Heck, in 5 years they change a lot. If the look remained the same, they could not sell the "new and improved version" to the same people.

From a manufacturing point of view, it is easier to build a box than it is to bend the metal to weird shapes to steamline it. So manufacturers KISS for as long as possible.

Let me correct something- Cadillac put a V8 into some their models some time around 1914. Ford had a flat head ford in production cars in 1932.
I don't know what the air flow would be in the old cars. The issue became known some time around the 1930's. By 1934 several cars had curved front ends and the open fenders towards the front had largely become a thing of the past for many makes some time around 1936.
The first car that I know of that addressed the aerodynamics was the 1934 Chrysler Airflow.
What I know from driving is that well into the 70's the body designs produced lift at speed.
Not much was said about wind tunnel tests until Ford got hot about winning in NASCAR and brought out what was called by some the "Areobird". I think maybe Chrysler used it on some of the Daytona models they put into production.
If you want to know- it would just be a matter of getting some model cars and testing them in a scale wind tunnel.
I might be wrong on some issues, here is a link on the matter