Five Carburetors: Why Not?

One V8 hot-rodding trick of the ’50s that never quite caught on was the 5×2 carburetor setup. But you know, it’s not such a terrible idea.

 

 

The photos we’re sharing here have made a few laps around the hot-rodding message boards across the internet, where they never fail to stimulate interest and discussion. The images depict an idea that originated in the early-to-mid-50s for souping up American V8s: the 5×2 carburetor setup, with an intake manifold specially cast (or modified from a production component) to accept five two-barrel carburetors. While the configuration never really caught on, it’s not as strange as it may look today.

 

The system above, apparently built up from a production Pontiac V8 intake manifold, uses five Rochester 2GC two-barrel carburetors laid out in an X pattern, with the center carb in the original stock location. The early Oldsmobile (1949-64) manifold in the lead photo is of similar configuration, and also includes Rochester-style carburetor mounting flanges. Another noteworthy was the Cadillac V8 in the 1950 Cadillac Le Monstre of Briggs Cunningham, which ran in the 24 Hours of Le Mans.

 

Here’s another angle of the Olds V8 manifold, above. So what were they thinking? In theory at least, the stock center carburetor would provide good idle characteristics and decent low-speed drivability, while the four outboard carbs provided the high-speed breathing and fuel capacity As a bonus, each two-barrel outboard carb was ideally located right on top of an intake port pair for good air/fuel distribution.

Drawbacks? Balancing five separate carbs can’t be fun, but much of that hassle can be avoided by eliminating the idle and low-speed circuits in all but the center carb. Next, this setup demands a throttle linkage that operates in two planes—bulky and complicated. The more conventional 3×2 and 2×4 carburetor setups weren’t nearly so fussy in that regard, and they were more than adequate for the needs of most hot rodders.

The idea wasn’t confined to hot rodding, though. The automakers played around with it as well, for example on the 1953 Ford X-100 dream car. (Read about the X-100 here.) This Ford experimental setup (below) used a Holley “teapot” carburetor in the central location with four 94-style two-barrels in the outboard positions. Of course, here in the 21st century we have no need for carburetors at all—they’ve gone the way of breaker points and wood-spoke wheels.

 

2 thoughts on “Five Carburetors: Why Not?

  1. The setup is actually pretty slick. Makes a lot more sense than six two barrels on the street. The linkage wouldn’t be that difficult.

  2. At one point, the Pontiac Super Duty “bath tub” intake -generally credited as the first Tunnel Ram- used a stock side draft Carter carb and a 90- degree elbow for the same reason. While idling on and off the trailer, or into the staging lanes, the AFBs could be left out of commission, preserving the plugs which would otherwise load up almost immediately.

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