This Trick Flow® Race carburetors feature an all-new die-cast aluminum main body, which has a lengthened venturi section for greater midrange torque and better airflow. The annular booster venturis are precision die-cast with CNC-machined billet aluminum inserts, for smoother and more refined air entry, stronger vacuum signal, less turbulence, and improved fuel emulsion, providing better combustion. The Trick Flow® Race carburetors use black anodized, billet aluminum, CNC-machined metering blocks featuring 3-circuit metering, changeable emulsion, idle feed, and intermediate bowl and feed discharge. The die-cast aluminum fuel bowl combines high strength with significant weight reduction. They feature dual threaded fuel inlets and outlets and dual sight glass holes to easily set the float levels. The Trick Flow® Race carburetors feature external linkage with four different links to select the amount of primary throttle opening before the secondaries open: moderate progressive (25 percent), medium progressive (40 percent), and full progressive (50 percent).