68 GT500/leaking Holley from secondary bowl

[ridgeter]

My 68 GT500 Holley carb developed small leak at bottom of secondary bowl area passenger side - surprise!  It drips right on top of intake where engineering part number is for about fifteen minutes after I turn off engine - about 1/2 oz. The car starts right up, idles smooth and engine strong but strong gas smell after shut off.

Carb was fully rebuilt by reputable shop few years ago but car sat awhile.

What is different? recently had carb tuned and transported from Texas to California. I found small screw sitting on the intake but I'm not seeing any screws missing. 

Wonder if it's simple fix.