With the initial success of the Gran Sport, Buick added several variants when the 1968 redesign occurred. Now available as the California Gran Sport, Gran Sport 350, Gran Sport 400, and eventually the Gran Sport 455, Buick had a GS for everyone. The top-of-the-line GSX offered more torque and standard equipment than any other muscle car of the era. But if you want to bring your GS into the modern era, we have everything you need to bolt a Gen III/IV LS between the framerails.

Holley is proud to be the home of some of the biggest names in aftermarket exhaust and to be a leader in domestic engine swaps. With brands like Hooker Blackheart, Flowmaster, and Flowtech, Holley has the perfect exhaust system for your ride. Whether it is a classic muscle car, late model muscle, truck, or Jeep, we have the exhaust systems available to make your ride stand out from the rest and perform at its best.