The covers we offer are made to fit over a 6-7/8" x 2-3/4" molded flange. I know they will fit Hurricane and FFR cars.
Not familiar with B&B and the molded OD size of the opening. The material is easily formed, if you prefer, we can supply flat screen instead of forming it.
https://prdcrrct.com/product/cobra-brake-duct-screen/
Paul