The technicians at The Carb Shop make this look easy, building a stout high-hp blow-through carburetor like they do here. Our technician, O.J. Bretzing, starts out with a basic Holley 950 HP carb and builds it up from there. First the butterflies are removed from the carb baseplate in order to gain access to the throttle shafts. New seals that can handle 30 psi of boost need to go into the shafts.