Excellent product , a must have for any 2001 7.3 .Very competitive pricing including postage to Australia. Thanks RIFFRAFF!

This is a better quality filter at a cheaper price than the 6637 replacement filter I bought at NAPA.

Great product and mod. Fit right on my K&N cold air intake.

Every time I place an order from Riffraff I always add 1 or 2 of these just to have a spare around. They work great i have been using them for years! Great Price and fast shipping. Dont get much better! Thanks RiffRaff Diesel

The conversion to this filter for my f250 was very simply. I have had it for 250 miles I can see more boost than a clean K and N filter

like others say you can get the pre filter and the 6637 filter for cheaper than your local auto parts store. definitely suggest the pre filter, it is very well made.

I used this to replace my K&N filter element. While the K&N is a reputable brand, I found that the truck was actually sucking the oil off the filter and I had concerns with its ability to keep the incoming air clean under some of the condition the truck experiences.

The 6637 is a serious looking filter, and with the protective prefilter from Riffraff looks impressive under the hood. I'm sure the combination of the prefilter and 6637 will provide plenty of flow and protection for the truck, and outperform the K&N in filtering performance. It fits the K&N intake tube, but I had to pull the K&N air deflector/ baffle from the truck that mounts behind the battery to make room for this filter. Well worth the effort, and another great value product form Riffraff.

Nice filter. Made in USA. Baldwin filter. Good buy.

Riffraff the best by far ,very fast delivery ,and the know their Chit ,everything as expected
Thanks