I have a 1968 RS with a 230 Cu IN 6 cylinder engine and wanted to have dual exhaust. I installed a 1975 Camaro muffler with a single inlet and dual outlet then installed the two tail pipes Tail pipes from 1976 throught 1980 can be used. Other than instyalling the extra hangers, the only modification that was reguired was to the pipe that goes over the rear axle. It needs to be bumper out from 2" to 21/4 so as to fit the muffler. I used the tail pipes for a 1975 Camaro and they fit very well and look and it sounds great.