Review on Spectre Performance Air Filter 9831 - Enhancing Air Box Efficiency by Larry Cho

Watch what you wear. Specter/K&N state that this unit (the largest) is only good for 660 cfm. If you do a bit of math, this works great for many standard small-block engines, but add a cam, headers, and a few other goodies and you're out of reach at the top end. I have it on LS3. It's basically a camp with a pretty beefy camera and headers. At 5800 rpm the filter is empty and the engine chokes. Well below the 7k redline the engine is capable of. I contacted Specter to see if I could install a larger or looser filter, but their engineers are too busy to contact me after weeks of waiting. This is a really nice device and well made. Definitely worth the money if it suits your application!