As you might have guessed, I'm a huge fan of Amsoil products (used 'em since 1979). I'm also a big believer in using the best product available for the purpose, especially when the benefits clearly outweigh the costs. If you want to do everything possible to virtually eliminate wear in your engine, you have Amsoil in it. There are more than enough test reports going back 25 or more years that clearly show this. Amsoil also has always offered a line of oil and air filters and other products. I have been resistant to use their air filters, or for that matter, those offered by K & N mostly because I just plain don't want to screw with a filter that needs to be washed and re-oiled. YUCK!
The good news is Amsoil has just introduced a new line of air filters that use nano-fiber technology. They filter smaller particles, hold more dirt, don't need oil, and unlike every other filter I've ever seen advertised, can be cleaned with an air hose or vacuum! Rather than trying to recap all the information, I'd like to direct you to Amsoil's own web pages for these filters:
These pages will pretty much answer all your questions. Unfortunately for us, they only offer one filter that applies to the Corvair, but it does fit a LOT of different Corvairs! If your 'Vair takes the AC A178CW filter (which also crosses to a Fram CA192, a Purolator AFP-67, or a K-Mart KA23, then you need an Amsoil EAA32. This covers the 1964-1969 cars, unless you have a turbo or a '64 or '65 with air conditioning. They're not cheap, coming in at right around $30, but what's it worth to you to have the finest and most convenient air filtration possible on your Corvair? And you don't have to mess with oiled elements, and get better filtration than the wet style filters offer! Naturally, you clean them and use them darn near forever, so in the long run they're cheaper than lesser filters. I say give 'em a whirl! You can get 'em from your local Amsoil dealer, from many retail outlets that handle Amsoil products, or order 'em right off the corporate website.