Here's the latest in vintage...
Here's the latest in vintage carburetion: left to right the Stromberg 97, the Holley 94, and the 9Super7.
Our hobby is full of contradictions; on one hand it's steeped in tradition, on the other it embraces the latest technology. There are rodders, like Editor Brennan, who love the latest, high-tech components. Brennan's gadget-oriented philosophy is "anything worth doing is worth making as complicated as possible"-if a computer, multiple sensors, and miles of wire is involved controlling any function he's happy. Throw in a couple of blinking LEDs and he's delirious. On the other end of the spectrum are those of us who consider simplicity the ultimate engineering accomplishment, no electronics, no wires, and the only mode is manual. Apparently there are more than a few who appreciate the uncomplicated approach. How else could the selection of brand-new old carburetors be explained?
Of all the carburetors that have ever been produced, two of the most popular have been the Stromberg 97 and the Holley 94. Today both are being reproduced-Stromberg Carburetors, a British company, offers the 97 and Edelbrock the 94; both are cosmetically identical to the originals with some unseen mechanical improvements. A third offering, the 9Super7 from Speedway Motors is similar in appearance to a Stromberg but will not be mistaken for one by those familiar with an original. Speedway has made several changes to the original design, including manufacturing the base assembly in aluminum rather than cast iron.
All carburetors have the same basic systems: an idle system to deliver fuel below the throttle plates when they are almost completely closed with the air/fuel ratio controlled by needle valves; a main system that delivers fuel to the venturi when the throttle plates open past idle; a transfer system that supplies fuel as the throttle plates open and the carburetor goes from idle system to main; a power system that provides a richer air/fuel ratio when the engine is under load; an accelerator pump to add fuel and prevent stumbling when the throttle is opened suddenly; a float, needle, and seat to control the fuel level in the bowl. Stromberg 97 and Holley 94 carburetors have these systems, but there are subtle differences in how they are configured. Let's take a look at the two designs individually and then compare them.
Nothing is cooler than multiple...
Nothing is cooler than multiple carbs and they can be made to work as great as they look. This classis three-two setup for a Flathead uses Stromberg 97s on an Edelbrock manifold.
Stromberg produced carburetors for a variety of automobile manufacturers but the versions that most hot rodders are familiar with first appeared as the Model 40 in 1934 on 85hp Ford Flatheads; the model 48 was introduced on V-8s in 1935 (the preceding were both rated at 170 cfm); and from 1936 to early 1938, 97s were installed on Fords (155 cfm). The smaller-model 81s (125 cfm) were used on the V-8/60s while the larger LZs (160 cfm) were found on the Lincoln V-12s. In addition to those factory-installed carburetors, what were known as Type I Stromberg 97s were manufactured by Bendix in South Bend, Indiana, as replacements for Holley 94s; most of these have the 97 logo. Replacement versions, designated the Type II, were manufactured by Bendix in Elmyra, New York, and have a 1-1 logo.
Holley 94s are often mistaken for Strombergs even though there are some obvious differences. Used as original equipment by Ford from 1938-57 and sold by parts stores as replacement carburetors 94s have always been more plentiful than 97 and as a result less expensive. Like many things that Henry Ford was involved in, the Holley 94 had an interesting beginning.