Air gap should clear no problem , at least it does on my car , using a Holley with the stock 340 air cleaner ,no spacer between carb and intake , that might be a problem with clearance , not sure
The air gap clears on both my 318, and my brothers 340 under stock hoods. I've used both Holley and AFB carbs with 3" drop base air cleaner. Trim the stud down to about 1/2" above the cleaner lid and you should be good