What I did for true cold air is:
First I got the whole Stock air intake out of the way. Then I did the intkae tube with 3 and 4 inch Poly pipe from the Throttle body to the MAF.
Then slapped a K&N conical filter on a 90 somethin 5.0 lincoln MAF and just swapped over the actual sensor from the stock MAF to the Lincolns'.
Then I just recently did the cold air part. I took a Tupperware Folder Holder with a lid Just big enough to fit my air filter into. Cut it down to size and secured it fully around the filter going just to the edge of the MAF to ensure a decent heat shield seal. To make the tupperware more heat resistant, I took duct tape and wrapped it all around the box even the lid. Then I took Heat rated tape, rated to 1500 degrees, and put it over the duct tape. Then I took "Engine Enamel" Spray paint that is engine heat friendly, so there are no problems in holding up to the heat, and sprayed the whole box. Keep in mind, all of these things will need to be done with the box out of the truck, with the air filter not in it. There is the heat shield part...
Then the Ram/ Cold Air..... I took Flexible ducting and a hole saw and went to work on my wheel wells' plastic insert. After the holes were done, I wrapped the ducting with more heat rated tape to keep the header heat away from them. To ensure a water tight seal in the airbox I took duct tape and shoe goo ( or RTV will work. Something sticky, just not gorilla glue or anything that gets super hard, cause things that are hard become brittle under heat and movement.) And went around the part of the ducting I stuck into the box from the top, down. The reason I did it that way is because what can come up through a hole can go back down. So then the ducting can flex once the self made "Gasket" around the ducting has set inside the box. I angled mine toward the front of the wheel almost sticking out of the fender but not. Cool thing is, they can always change posistion, so if you are in a little deeper stuff and it is gettin sticky, angle them up outside the fender.
I wish I could explain this all better and could figure out how the flip to get pix on here not being a member. If I could show then I could tell a little easier, but I hope this helps someone...