I'm having the same problem with that very same needle and seat. Mine is in a '46 Coupe that is running a "Ford/Holley" model 94 Carb. Starts right up when it has been sitting and is cold. Runs and idles great. Floods when you shut it off. You can see raw gas leaking out between the body and the base. I plugged the power/economizer valve just to eliminate any chance that it might be leaking by. It is not.
That needle and seat seems to be the problem. It is, in fact, not a needle but, a small rod pushes up against a disc that is supposed to shut the fuel off. I don't believe it is working.
New Edelbrock rebuild kit on the way from Summit Racing. The kit appears to have a true needle. It may be Viton tipped, it was hard to tell. I will stick it in this weekend and report back.
Dale