@David Stroud IM Roadster D - " and the airflow in there is somewhere between berserk and who really knows. It is not rad friendly. "
Now, there is the rub, right? No one really knows. The fact that the Porsche engineers use the top of the airfoil to draw air is confusing, because basic physics tells us that area is low pressure, thus the vent will tend to suck air out of the engine compartment. And the same physics tells us that large flat pan under the car is a high pressure area compared to the area above the vent, and thus air from under the car would tend to move from the bottom through the engine compartment and out the vent. I wish I could talk with one of the original engineers who could tell me that the location of the vent was a cost compromise and not an optimal solution. Also, the engine tins in the 356 seal off the engine compartment from the high pressure area underneath the car possibly making the pressure difference between the top of the car and the engine compartment negligible. My car has no engine tins and the engine "firewall" is located farther forward with no air seal. Hmm.
A part of me wants to locate the gas tank in that cavity because it would take the gas tank away from the front in case of an accident and put it in a safer location, and a part of me wants to put the radiator there just to see what happens, and a part of wants to make it into interior cabin space.
Luckily, some stair parts showed up yesterday and I have to go back to work on the stairs which will give me some more time to mull over my dilema.