Flowmaster 40 series mufflers, the original two chamber Flowmaster muffler! Flowmaster 42441, 42541, 42443, 42543, 430402. Preferred by Mustang other muscle car owners. Flowmaster 40 series mufflers feature all welded steel cases (no stamped seams to blow out) with internal chambers to dampen sound. (no fiberglass packing to blow out)Flowmaster 40 series mufflers are made of extra heavy gauge steel, aluminized for rust protection. Flowmaster 40 series two chamber muffler 42441 42541 42443 43543 43042 40seriesAPPLICATIONS:: Flowmaster 42441Flowmaster 42541Flowmaster 42443Flowmaster 42543Flowmaster 430402 We welcome CANADIAN customers! For ordering information, click on "Orders To Canada" at the top left side of this page. PAYMENT METHODS: PayPal, Visa, Mastercard, Discover, American Express, money orders.