Holley carburetors can be identified by matching the list number imprinted on the carburetor with the list numbers in the company's catalog of performance products. On square flange carburetors, the list number is located on the front driver's side of the choke horn. Dominator carburetors do not have a choke horn; the list numbers for these are placed on the venturi area of the throttle body. Four barrel carburetors have their list numbers imprinted on the throttle body's driver's side.
Holley carburetors are manufactured by Holley Performance Products. The company, which was established in Bradford, Pennsylvania, is now located in Bowling Green, Kentucky, but it was once based in Michigan and served as one of the leading producers of carburetors for vehicles built in Detroit. It annually makes carburetors for NASCAR's Sprint Cup team, and four decades' worth of NHRA Pro-Stock champions have had a Holley carburetor under the hood. It also produces parts such as intake manifolds, cylinder heads, performance fuel pumps, fuel injectors and aftermarket engine additions that increase performance in street, race and marine vehicles. Holley Performance Products is also responsible for products sold under the brand names of Nitrous Oxide Systems, or NOS, FlowTech, Earls, Hooker Headers and Weiand.