My NAPA dealer gives me the fleet price on the 6637s. I got my first one 7 or 8 months ago for $25 and just bought 2 more for $30 each incl tax. (Got one for a buddy too). Try asking for the fleet price. If all else fails and you think it'll be worth it to you, I can try to get you one at that price and ship it to you. It might end up costing you $40 or a bit more.

 

I need to correct myself on that WIX number it is 46637,and crosses to a Baldwin PA2818 and a Napa Gold 6637.This filter flows 425 cfm.If you want to go a little bigger a Wix 42790 flows 680 cfm,But it is a little bigger 2 inches in dia. and 1 inch longer.Not sure if it will fit under the hood?

 

You can try some of the truck part houses to see if they carry them. here are some part numbers of the same filter
luberfiner LFA2533
baldwin PA2818
Donanldson BO85011
fleetgaurd AH1141

 

Or check out some of the bulk oil places that supply trucking companies, they should also supply there air filters too.

 

Thanks for all the info guys. I believe he ordered one from fleetfilter.com. big difference $27 vs $62.

 

got mine for $32 at the local napa store (they were listed as $61 online but I wasn't about to argue)