Help with Holley fuel leak

[custom1970]

I was hoping someone could tell them me how to fix a small fuel leak, this is not my actual carb, just one close to it. I have a small amount of fuel leaking from around the small (approx. 3/8") disc i've circled in the pic. I just re-installed the carb. after having it re-built and have a call into the shop (in NJ) but usually takes a day or two for them to call back. I was hoping there might be an easy fix i could do this weekend so i don't have to ship it back to them...., Any help would be appreciated, thanks

oh, other than the small leak, it ran great