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.

When adding a 5 or 6-speed transmission to your classic muscle car, we have the driveline conversion components you need. Whether it’s a shifter, transmission crossmember, or tunnel patch, we have the brands and components you need to upgrade and complete your driveline conversion. Most parts in this category assume you will be keeping the original engine. For engine and transmission combination swap parts, look to the Engine Swap Parts Category.