- 4A Troubleshooting
- Stromberg 4A Power
- Stromberg 4A Accelerator Pump System
- Stromberg 4A Float Adjustment
- Stromberg 4A Starter Switch
- Stromberg 4A Fast Idle And Starting Aid
The Stromberg 4A (often referred to as the 4Aero) was a heavy-duty, four-barrel carburetor produced by the Bendix-Stromberg division.
The 4A was essentially designed as two two-barrel carburetors merged into a single casting. It is a monoblock design (meaning the main body is a single piece) and features:
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Mechanical Secondaries: Unlike later vacuum-secondary carburetors, the 4A relied on a mechanical linkage. The secondary bores remained closed until the primary throttles reached a certain angle (usually around 40–50% open).
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Auxiliary Valves: To prevent the engine from bogging when the secondaries were kicked open at low RPM, it utilized weighted auxiliary air valves above the secondary throttle plates.
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Double Float Bowls: It featured two separate floats and fuel bowls to ensure consistent fuel delivery during heavy acceleration or cornering.
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Choke System: Most versions used a remote thermostatic choke coil mounted on the exhaust manifold, connected by a rod to the carburetor air horn.
What It Fit
The Stromberg 4A had a very specific and relatively short production run for passenger cars, primarily serving the Buick lineup during their transition to higher-horsepower overhead valve (OHV) engines
| Year | Make/Model | Engine |
| 1952 | Buick Roadmaster (Series 70) | 320 cubic inch Straight-8 (Fireball) |
| 1953 | Buick Roadmaster & Super | 322 cubic inch V8 (Nailhead) |
| 1954 | Buick Roadmaster, Super, & Century | 322 cubic inch V8 (Nailhead) |
| 1955 | Buick (Various Models) | 322 cubic inch V8 (Nailhead) |
Note: In 1952, the 4A was the "big news" for the Buick Roadmaster, helping the Straight-8 reach 170 hp. By 1953, when Buick introduced the "Nailhead" V8, the Stromberg 4A was used alongside the Carter WCFB. By the late 1950s, Buick moved away from Stromberg in favor of Rochester and Carter four-barrels.
Maintenance Insight
Because the 4A uses a pot metal body, a common issue found today is "warping" of the air horn or the throttle body if the mounting bolts were over-tightened. When rebuilding these, it is crucial to check the flatness of the mating surfaces to prevent vacuum leaks.
