Carburetors 101

Street Carburetors - Driving on the street is actually one of the most demanding environments for carburetors, because of the endless array of varying conditions encountered almost constantly. To accommodate these ever-changing engine needs, carburetors intended for street use typically have features that make them more readily adaptable. These features often include vacuum secondaries, which are more subtle and flexible in their operation, along with such amenities as electric- or manual-choke systems.

Performance and Race - When you want to go beyond mild street performance and into the realm of more serious power and perhaps competition, carburetors with mechanical secondaries and two instead of one accelerator pump become a more effective solution. These so-called “Double Pumper” carburetors give you more consistent, precise, and tunable secondary actuation, along with a larger shot of fuel on acceleration, to minimize bog when the throttle blades are opened abruptly. Many of Holley’s Performance and Race Carburetors also have billet metering blocks, which have better resistance to fuel corrosion and lower chance of porosity in the fuel block. But, at the same time, most of Holley’s Performance and Race carburetors still have a choke system, to make cold starts easier for street use.

Professional Race - Racing carburetors operate in the narrow, specialized environment of competition. This means that their whole job is focused on feeding maximum horsepower engines as efficiently as possible. For that job, the best choices are mechanical-secondary carburetors with two accelerator pumps – also known as “Double Pumper” carbs. At the same time, race engines benefit from billet metering blocks for better durability with harsh fuels and lower chance of porosity. Holley’s Professional Race carburetors generally eliminate airflow-impeding choke mechanisms, to allow maximum performance.

Marine - A lot of Boats are powered by V8 engines, but that doesn't mean they can run an automotive carburetor. To prevent any issues, marine carburetors have a J-shaped vent tube that directs any vented fuel harmlessly back into the carburetor.

Performance 2 Barrels - With names like Six-Pack, Tri-Power, and three deuces, the three 2-barrel setup is an intrinsic part of muscle-car history. Holley offers direct replacement 2-barrel carburetors for popular multi-carb setups like these, as well as bolt-on direct replacement carbs for mild street engines and motors required to run a single-two barrel for competition rules.

Specialty - There are plenty of times where carburetors are forced to operate in unique and demanding conditions that a typical general-use carb simply won’t tolerate. Car owners running superchargers, tunnel rams, or working with primitive OEM carbureted emissions controls need the focused approach that Holley Specialty Carburetors deliver. These highly specialized designs make it possible to get the advantages of Holley carburetors, without giving up your preferred engine configuration.