Did my due diligence and went with this.
35" x 3.75 ≈ 4.23
31"
In my case I'm overgeared with 4.88s ON PAPER. But on the road behind the wheel using my butt dyno, it feels like stock performance.
Here is the "Breather" without the catch can.
https://www.uprproducts.com/12-21-3-6-jeep-baffled-billet-one-way-valve-cover-crankcase-breather-kit-upr/
What's the point of this?
It's called a one way breather oil cap.
https://www.uprproducts.com/18-23-jeep-wrangler-jl-and-gladiator-3-6-l-billet-oil-catch-can/