I saw a Mod someone had done on the intake using an electrical box cover that had a Ball valve mounted to it. it had long bolts that passed through the intake slot with a piece of flat steel on the inside that braced against the inner wall once the nuts where tightened the pit wall was sandwichedbetween the flat steel & the cover. There was a Gasket on the O/S to make it air tight. It was a slick fix to that problem.
I never met a Cow that I didn't like with a little Salt & Pepper! Certified PORK-A-HOLIC