Originally Posted by AOx4
The 6637 is actually rated at a lower CFM than the stock filter. Not by much, but by some. Your truck probably wont notice but thats that. It filters much more though, and lasts a lot longer.
I run a 6637 and it has served me well but I dont love it. AIS is a much better filter, both air flow and filtration are improved over the 6637, but it is a tad expensive.
Kinda difficult to do both of these better and remain the same size or smaller.
The 6637 filters good. It flows good because of the surface area of the filter.
This gilter is meant to keep engines alive in very rough conditions and will serve you great on your truck.