Ok, first off, let me put forth an objective. The idea here is to help folks come up with a plan for modifications, and then analyze some of the potential mods. I am not trying to say 'this is what you should do to your car', just help somebody come up with a plan that will help them get to the point they are trying to achieve. By no means do I have all the answers, so I'd really like to see comments.
Now we've all done the 'Hey, there's a cool part I'd like to try' routine at one time or another. But before we rush out to buy, there are a few things that we need to decide about the car first:
This is better answered if you decide if you are more interested in building the car to it's legal limit, or just want to modify it to some point you're happy with and then see what class it's in. This is a really important step, as there are quite a few mods (disk brake conversions, for example), which will move you up to Prepared (more on the prep levels in a moment). In many cases, you may find that only one or two of the mods you want will bump you up a class.
Driveability of the car. Is this a daily driver? Is it strictly a trailered car? Somewhere in between? How far will it be driven at a time? To events only? To conventions? Across the parking lot?
Level of competitiveness. This is a really tough one. Doug Roe and Tazio Nuvoulari notwithstanding, there are *very* few people on this planet who will do well at an autocross their first time in their daily driver.
So, we need to consider the event series we want to run in. Is this car for a local series? SCCA regional? Nationals? Unless you are unfortunate enough to live in the same town with your National class champ, you'll be able to do a little less development and still do well at a local event.
Ok, quick description of SCCA classes. These work in much the same way as the CORSA rules, but bear in mind that the actual rules are very different. There are two components of classing, class and prep level. Class is the group of cars that compete with each other. Prep level is how much the car can be modified. A caveat: I don't yet have the '98 rule book, so there might be some changes coming. Here are the SCCA classes that Corvairs run in:
Now let's talk about prep levels:
more details here.
Stinger stuff. Not many people have developed cars for this class, the notable exception being Seth Emerson. Carbs are a big headache, since the heads cannot be modified.
This class is basically for old road race cars. Most of the serious go fast mods like vertical fans, triple Webers, and suspension relocation kits, are aimed at this class. Note that most of these parts are also illegal for ESP. Most of the current Corvair race development is aimed at this class, partially because the parts can also be used in road racing.
Newsflash: Effective Jan 2000, Corvairs may weigh 1850 pounds in C/Prepared. tube frame cars have a 185 pound weight penalty, so the minimum for a tube frame car is 2035 pound. Good luck!
Which means that a full tube frame, mid engine V8 Vair is legal for this class. Harlan Colburn campaigns just such a car. About the only thing you couldn't do is run a front engined Corvair. Another possibility is to run something else with Corvair power, like Warren Leveque's Ultimate Spyder Roadster.