Thanks--the "swirl coefficient" would, I assume, reflect the buffeting effect from the air stream having to make the transition from horizontal to vertical. If that is so, I would assume that the "X-Stream" filter tops we have been discussing here, which in effect have filtration material on the top of the air cleaner, would offer reduced buffeting since they would already be presenting airflow in a downward/vertical direction.
http://www.knfilters.com/search/prod...x?Prod=66-1101
While not exactly the same as I used on my GTO, here's a Mr. Gasket product that does look similar:
http://mr-gasket.com/ProductDetails....txtSearch=2085
I see the "glass-fiber" filters flowed best, but obviously they would be a poor choice for a high-mileage street engine. NASCAR engines are rebuilt after each race, so if any fiberglass should find its way into the cylinders, it would not present that much of a problem.
Great article, thanks!
Cheers from Dugly
