I worked on the air cleaner. When I first opened it up, it had a big mouse nest inside of it. I couldn't get it cleaned it up because of the metal mesh. I removed the mesh and decided to replace the guts with a non oil bath filter.
I had various parts of things I've kept over the years as "resources". I bought a new K&N filter that fit over the intake tube, but I wanted to make it look as original as possible. Even though this is under the cab, I knew what it would look like. I used a piece of UHMW plastic as a spacer and then used various fittings to adapt the K&N. I sealed this inside the original filter housing and secured it with screws.
Once it was all put together, I mounted it and attached the hose. It all turned out pretty good, I think.