Unfortunately, your going to have to make your own. I am not aware of an aftermarket snorkle for the S-series trucks. If you find one, post up.

 

One more thing to add to this discussion is that if you are running in dirt/mud/water, it is a good investment to purchase a foam prefilter for the outside of your k&n. K&N sells them for many of their cone filters. This will increase the filtering efficiency without a big hit to the airflow efficiency.

 

I've been considering the Airaid intake for my truck, 4.3 TBI. I've heard good things about 'em and the price is similar to the K&N.