The original connector tube wont be long enough to reach the secondary bowl after we add the new secondary metering block. QFT provides this longer aluminum one with an improved seal design in the correct length.
The connector tube just presses into the bowls using the supplied seals. With the tube in place, we are ready to install the secondary bowl.
Here you can see the difference in lengths between the original bolts and the supplied QFT bolts. Since we are converting this carb from one metering block to two, we need one set of longer bolts for the secondary side.