I put some other peoples ideas together to build an intake for my truck and I wanted to list my experience with it and elicit any input or ideas.
I used a K&N RU-3040 filter. To mate it to my intake I cut a ring off off a piece of 5" black abs pipe and inserted it inside the end of the filter (this fits snug). I was able to then put my stock intake hose directly onto the outside of the filter and snug it down with the stock hose clamp. I was very suprised at how well it all fit together.
Currently I have the filter sitting in the lower half of the stock air box. I plan to use a template that I downloaded to cut an aluminum heat shield/box out to use untill I can engineer and build a better moustrap, hopefully incorporating a snorkel of sorts to grab some clean fresh air.
I had a great deal of trouble with large pieces of pollen and leaves off oak trees getting lodged in the filter pleats and making it a pain to keep clean. I could not find a K&N filter wrap or prefilter in stock in my town. In search of a solution I found that I could fit a shop vac wet pickup filter over the K&N filter and two of them were long enough to cut to fit. Now I have a great prefiiter for about $10 vs the $40 they want for the K&N 25-3918. I also picked up some filter elements for a window unit air conditioner and plan to use one with two strips of velcro for an alternative to the shop vac prefilter.
1999, 2500, 4x4, 5 speed, 4 door, lb, large cylinder k&n filter, diablo power puck, FMS blue box, Vulcan fuel pump relocation and big lines, BFG AT KO's 315/75/16 on 10" aluminum rims, Rough country leveling kit, 135,000 miles.