On the outside it’s all Genuine 97. But on the inside, a BIG 750cfm, with improved fuel circuits and ported vacuum, take the hot rodder’s favorite carbs to a new level of performance and drivability.
All-New Stromberg BIG97 The Stromberg BIG97 is a totally new carburetor, available as separate Primary and Secondary models or a Tri-Power with special package deals on Small Block Chevy linkage and fuel line. OE, Chrome, Black & Chrome, and Barn Find finishes are all available, with optional cable choke and/or LZ-style push throttle. Click a tab to find out more!
55% more airflow than regular 97s
BIG97s move up to a 1.175in venturi with super-efficient 20 degree entry angles. The accelerator pump discharge jets are smaller and well out of the booster airflow. And flared exit cones build power by slowing the mixture down to reduce turbulence into the manifold plenum. The result? 250cfm per carburetor - some 55% more than our own regular 97s.

New 'early plenum effect' boosts top end power
A new, oval cut-out, just under the throttle plates, allows any cylinder to draw from both barrels, combining the easy drivability of a dual plane intake with a boost in top end horsepower more usually associated with a single plane intake.
New power valve circuits improve fuel conditioning
A new power valve (Primary only) feeds top end enrichment directly into the emulsion tubes, significantly improving fuel conditioning for more top end HP on less fuel. How? Because the more it emulsifies the fuel, especially at high rpm when manifold pressure is low, the easier it is to atomize, distribute and burn.
Ported vacuum adds mid range torque
BIG 97 Primaries come with a swap-in fitting to provide ported vacuum for your aftermarket distributor. Ported vacuum has been seen to improve combustion efficiency in cruising mode, helping engines run a little smoother and cooler, with more torque and moderate improvements in fuel mileage.

All Genuine 97!
Everything that’s made the Genuine Stromberg 97 so popular over the past ten years is built into the all-new BIG97: An early style cast iron base for low heat transfer. A reinforced air horn casting to eliminate warping and leaks. High tech gaskets. Stainless steel levers, linkage and springs. Original-style riveted throttle and choke shafts. And more.

Runs out of the box
BIG97s come ready to run with factory jetting dyno tested to suit a typical 350ci hot rod Small Block Chevy Tri-Power. As with any carburetor, rejetting may be required for other applications, high altitude, local gas, ethanol content and more. And a wide range of jets and power valves is available.
 Leadfoot’s Tech Center Tips
To make the most of your BIG97’s improved airflow capability, some intakes may need opening up around the bores and down into the webs. You’ll find full instructions on our Tech Center.
All-New Stromberg BIG97
All-New Stromberg BIG97
All-New Stromberg BIG97
All-New Stromberg BIG97
All-New Stromberg BIG97
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