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.
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
BIG97 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 smoother and cooler, with moderate improvements in fuel mileage and more torque through the mid-range (typically 3 to 4 ft-lb).