This is the brass deflector that is generally missing from your front or rear carb. or both. I have checked in my "Rochester Carburetor Parts and Service Manual" and see that these deflectors were on several different year carburetors. The deflectors help Atomization, the breaking the liquid fuel into very small particles so that it can readily vaporize and mix with the air. With the fuel broken into small particles, there is more air contact. The more air contact-the better the vaporization.