K&N makes filters, but they take a bit to get. I had to have them make a custom filter to fit right on the base of my Dominator carb (no air cleaner bottom) and fit a 9" top for the carb below. It's not a lot of filter, but does the job on a 527" big block at 8500.
http://performanceunlimited.com/cobra/barrygrant.html
Also, for those wondering just how a K&N does it's magic, there really is no magic... just a little here, and a little there, all wrapped up in one red looking filter. Here's more info here...
http://performanceunlimited.com/illu...ercompare.html
Also, we wrote a magazine feature for Four Wheeler on a build-up project, and one was a filter test... although not exactly relevant to a Cobra, it does show that the K&N claims and gains are real.
http://performanceunlimited.com/proj...ircleaner.html
/Randall