Top End Needed

Are you talking about the car in your pic?

Is your carb sealed to the scoop? How much clearance do you have above the carb vent tubes? I believe Holley calls for 1".

I've seen some sealed carb/hood scoop combos cause some weird issues. Airflow can do some strange things with some scoops on the outside as well as in the inside. A friend cleared up some issues when he cut some openings in his '65 Satellite/Hemi scoop seal!

Just a though that will only take a run to confirm.

OEM jetting on a 3310 is 72 front and the plate is equal to 75 or 76 in the rear. That might be lean for your engine.