Exhaust manifold: 403 Olds 77-79 RHS - USED ONLYRHS manifold.. USA passenger Side Olds 403's used this manifold for the Firebird TA series.. LH & RH are not made .. This is USA passenger Side Also used on various 70's Olds engines. (Click on the image to enlarge.) LH often crack.. RH same but finding them is tough. Many have lugs broken off that can be fixed by a exhaust specialist normally. Casting # is GM 563619 RH and then some shift production #'s that don't matter. These ones are good.. we try