Stromberg STROM9510A-BIG-P Genuine Reproduction 97 Carburettor - New Primary Carburettor Big97 - 250CFM Plain Finish

The BIG97 Primary features 250cfm airflow with significantly improved fuel circuits, and provides ported vacuum for your modern aftermarket distributor. It can be used on its own, in multiples (with direct or progressive linkage) or as part of the BIG97 Tri-Power.

55% more airflow
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.

New power valve circuits improve fuel conditioning
Feeding top end enrichment directly into the emulsion tubes, BIG97 Primaries significantly improve fuel conditioning for more top end HP on less fuel.

New 'early plenum effect' boosts top end power
Allowing all cylinders to draw from both barrels gives you dual-plane drivability with a single-plane style top end horsepower.

Ported distributor vacuum
Switch in the brass plug (supplied) and connect your distributor to improve combustion efficiency in cruising mode. You'll run smoother and cooler, with more torque and better fuel mileage.

BIG S-jet twin-ball inlet valve
Accepts big diameter 5/16in hard line (regular 97s take only 1/4in line), plus regular Stromberg fuel fittings.

All Genuine 97!
Everything that makes the Genuine Stromberg 97 so popular is built into the all-new BIG97. From the cast iron base to the reinforced air horn casting and everything in between.

Runs out of the box
BIG97s come ready to run with the following jetting (see below). As with any carburetor, rejetting may be required for other applications, high altitude, local gas, ethanol content and more. A wide range of jets and power valves is available.

BIG97 Primary jetting:
Main jets 0.056in Power valve #65 Accelerator pump valve #60 Note: This jetting is designed for Primary use as part of the BIG97 Tri-Power. Smaller jetting will be required when using BIG97 Primaries in multiples.

• All Genuine 97 on the outside
• Totally new on the inside
• BIG 250cfm airflow - 55% more than a regular 97
• New power valve circuits improve fuel conditioning
• New ‘early plenum effect' boosts top end power
• Ported distributor vacuum adds mid-range torque
• BIG S-jets accept 5/16in hard line
• Runs out of the box