Air intake

[Cobrajet]

I have a Mac cold air intake on my 99 PSD, are these better than the K&N
or should I put the stock air box back on???

[Josh40601]

bumping this to the top. Interested if it is worth the cost of switching to a 6637 filter and cover over this one.

[dieselcrawler]

Never heard of the mac... but have put DIY 6637 intakes/filters on all my trucks, and my buddys. Highly recomend them, why pay big bucks for a name when you can get a great HUGE filter for less?

And haven't heard enough good anything about K&N to ever put one on my trucks, heard too much bad stuff... seems to be mostly related to the drop-in filters made by them for the stock air boxes, but if you scrap the stock air box anyway, just go to the 6637... huge filter, cost about $35-$45 once a year. It's less cost than an oil change, and you do how meny of thoes a year? I do about 10... between 4 trucks, all 7.3 PSD's, so the air filter factor isn't much in the maintnance budget.

[Josh40601]

My truck had the Mac on it when I bought it, which is why am wondering if I should keep it and clean it, or just go to the 6637. It's a big style filter VERY similar to the AFE.