How to make your own intake box
 

Saw this and I figured it would be a great read and tutorial for those interested.

https://nasaspeed.news/toolshed-engineer/build-your-own-cold-air-box/

One other thing to keep in mind for such a large / deep area like ours is that you can just build a lid for it rather than worrying about trying to get a perfect seal to the under hood due to the open top.

In their application, it's a pretty shallow hole so a lid might be tough, but we've got plenty of room.

You're not pulling any air from the top anyways - all the air should be pulling from behind the headlight/ the fender well, so open vs close top shouldn't make any difference in performance.