i made my pan out of gal. metal thats about 18/20 " long and about 12" wide then i cut the bottom off of a air cleaner that i had laying around and order the foam from jegs that is fire ret. use some inter. spary adh. to seal foam to metal been like that for about 6yrs now and it fits pretty good to the hood i dont use a air cleaner but i dont drive my car very far 10miles top.mostly strip time.....