I have never worked on Pantera aero but here is some general information that works. Each type of car of course is unique because of interaction of the front with the side, rear and radiator openings.
I spent a lot of time in windtunnels when the engineers used to say that aero was 50% science and 50% black art.
Now the computer simulation programs are so good that Audi race car designers tell me that they do not even test any longer, since the real loss is less than .04%.
If you have a front that is high enough to let air go under the car then a smooth underbody will help a lot, but may not be the right way to go for a Pantera. The French used to always let the air go under, but that was on small cars with small engines requiring very little cooling flow.
Most modern sports and production cars go the following way.
If you put a front spoiler one inch below the lowest part of the car then you are wasting your time on the underbody, the gain will be minimal. The front spoiler should be located vertically at the rear edge of the radiator, if possible. This location is easily accomplished, works well and is not very noticeable as well as being out of the way for curbs. This will create a vacuum behind the radiator and help to draw air through it. It helps cooling, and sometimes drag, to seal all openings around the radiator with some of that gray waterpipe wraping insulation. You can break it easily and force it into all the openings that allow air to get by the radiator without having any effect on cooling. It also relieves the vacuum under the car adding to stability at speed.
If you have lift problems a lower spoiler than one inch will work. The lower spoiler will prevent air going under the car, and pushing the front of the car up and unloading the front suspension. Start with the one inch first as that will also alleviate pressure on the underside of the front by allowing more air to go through the radiator. Add length to lower lift. One inch does not sound like a lot but once you get maximum flow, more does not help.
Large low spoilers will induce high drag. Start slowly with come foamcore and duct tape to experiment with the right size spoiler. You can drive around at low speed, 50 MPH and see the results in cooling. A lot of tape and 1/2 inch foamcore will allow you to go much faster. The pressure at high speeds is very high.
Keep in mind that the bigger the front spoiler gets, beyond what is required, the higher the drag will be, very bad for fuel economy and top speed. On spoilers both front and rear, the center one-third of a spoiler is where all the work is done. Spoilers in the front that wrap to the tires are cleaning up the flow around the tires.
If I was doing a Bonneville speed run in a Pantera I would tape up all the hood and door cuts, the window offsets, the sidewindows and windshield and lower the car as much as possible. I would add a small spoiler at the front and put a one inch vertical spoiler across the rear so that all the messy air coming off the roof will brake off clean. A small vertical edge could also help at the back on both corners. That would reduce the aerodynamic wake, essentially diminishing the vacuum that is pulling the car back. Also add Moon discs to the wheels and go with narrow tires. A hard horizontal piece added to the rocker edge would improve high speed stability.
The trick is to get the best cooling, appropriate lift at the front and a clean break at the rear to optimize top speed and fuel economy. A radiator that is flowing more air than necessary will allow the opening to be made smaller, reducing drag also. If water is entering a cross-flow radiator at the bottom, before cooling, then you can experiment with cutting the airflow at the top, gradually reducing the it until overheating starts. That will optimize the flow. If it enters at the top then you can reverse the process for experimentation. Diminishing airflow through a radiator reduces drag.
A good way to see all of this is to examine some new sports cars like the Lamborghinis or the Ford GT, a great modern aero example, both are mid-engine, like the Pantera.
Dick Ruzzin
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