Upgrade your 1989-1993 5.9 Cummins with the MBRP S6148AL Installer Series Turbo-Back Exhaust System. Constructed from durable aluminized steel, this 4" exhaust system enhances performance with a rich, mellow exhaust note. The system includes a mirror-polished, T304 stainless steel tip for added style and is designed for easy installation using common hand tools. Fits regular cab models; extended cab models require an adapter.