Holley Carburetor Specifications

Holley produces a wide range of carburetors. Each product is made to serve a different purpose, so the specifications must alter for each carburetor. Holley is the only modular carburetor company that has run for over 100 years. They have helped every NASCAR champion since the 1960s.
Metering and Kickdown
Some Holley carburetors, such as the 650 CFM Ultra Double Pumper, have black anodized billet aluminum metering blocks and a base plate with black hardware. Other carburetors, like the 1050 CFM Ultra Dominator, also have billet aluminum metering blocks, but they have interchangeable emulsion, power valve channel restrictions and idle feed. These carburetors come equipped with Ford A/T kickdown.
Choke and Ports
Holley carburetors have fairly standard ports, but the chokes vary from piece to piece. For example, the 650 CFM carburetor and the 600 CFM carburetor both have one timed spark port, one PCV port and one full vacuum. The 600 CFM comes with a manual choke, however, while the 650 CFM is equipped with an electric choke.
Other Features
Most Holley carburetors are made of aluminum. Some parts of the products are made of other materials as well; for example, the 650 CFM has glass fuel-level sight windows. The 600 CFM comes with a "Next Gen" needle and seat design that allows the user to not worry about external float level adjustment. The 1050 CFM is built with dual fuel inlets and slabbed throttle shafts.