The Buick Gran Sport was the apex of performance luxury in its time. When equipped with the legendary 401 cubic inch Nailhead engine, the Gran Sport pumped out 325 hp and a whopping 445 lb/ft of torque. If that doesn't get the job done, we've made dropping in a Gen III/IV LS engine a bolt-in affair.

From Ford Flathead to GM Gen V LT, and including everything in between like small-block and big-block Ford and Chevy, Gen III/IV LS, Coyote, Hemi, and more, we have the parts to coax more power out of the engine under the hood of your hot rod.