Flowmaster introduces our new manifold downpipes for 1964-1966 Ford Mustangs with 289 V8 engines. These 2.50 in. mandrel bent 409S stainless steel pipes include the 2-bolt flanges, donut gaskets and donut sleeves. Works with kit #17273 and #817273. These downpipes are covered by Flowmaster's Lifetime Limited Warranty.