I have a question. Iwas looking in Summit and Jegs catalogs and saw catback exhausts for the monteSS and GN but not for any other Gbody. Will these fit my Cutlass or is there a difference? The car runs great right now so I dont want to mess with the emissions by putting a dual exhaust on( at least not for a few years until I can afford to swap to a ROCKET 350.) Oh ya the engine size down below. Thanks for any help.