I'm wondering what the purpose would be. The only time I have seen a need for this is a complete restoration. The rotation is for the frame only which would be just fine on a Fiero with no fluids as it would be with any other car.
I would never try hanging the car from the suspension. You would be putting tension on compression designed components.
For $3,000 or less you can get a 2 post lift that will satisfy a lot of needs. I have had one for nearly 15 years and can tell you that it is pretty good even on a frame stripped application.
So, the consensus seems to be that, if I removed the engine and fluids, this could be done if bolted to the frame? Would I have to remove the windows?
I am a little worried about the gas coming out of vents comment. It sounds as if, were you to jave a wreck and flip, gasoline would be everywhere, in addition to other troubles.
Gasoline I wouldn't worry about so much. The fuel system is sealed (there's a reason a gas cap pressure test exists in emissions and safety tests). Unless you already have a fuel leak, the fuel system should be fine if it were to be turned upside down. The coolant, oil, and other fluids though, I would be more concerned about.
Really though, I wouldn't want to turn any vehicle upside down with fluids in it, that wasn't designed to be upside down at some point during its service life. And I don't see why you'd even want to turn a fully assembled and running vehicle upside down or sideways.
Also, what NASCAR are you talking about that weighs 5000 lbs? Winston Cup cars are more like 3400. The trucks are pretty light too. They are full race vehicles after all. I'm surprised the cars even weigh as much as they do.
This is the idea. Why not keep my car nice? I won't always just be able to buy a nicer car.
Right, but you really only need to turn it around once, when it's stripped bare and you're totally restoring the frame. If you keep the undercoating and everything fresh and clean, it will last a very long time, and you don't need a rotisserie to do that. I'm sure you don't want to go draining the fluids and doing a total restore every few years.