WTH is this thing that's leaking on the back of my ThermoQuad?

I just got done replacing the timing set on my 440 and when I tried to fire it up, I get a gas leak from this device that is mounted on the back of my TQ.

Can anybody please tell me what this device is, what would cause it to leak, and how to correct the leak?

Thanks very much.

I believe that is the bowl vent solenoid.
Maybe because the float are set too high or have something stuck in the needle and seat.

Maybe this?
Thermoquad 4 Barrel Carburetor Bowl Vent Solenoid Gasket