Holley 4150 dripping fuel from primary discharge nozzle?

When I rebuilt my Carter, I had the same problem. Turned out I hadn't torqued down the new seats properly and it was leaking fuel through the seat threads.

Not familiar with Holley's, but with the Carter, you can take the top off with the floats still attached and blow on the fuel inlet with your mouth. If it still leaks air when you lift up on the float you've got a problem with the needles and/or seats.