Those holes will disturb the airflow into the primary introducing a side shear effecting distribution, no???? It would have been interesting to see an AF ratio before and after mod. Including cylinder to cylinder on a dyno. Carter and the OEM had a lot of different strategies with the AFB. For some of the Chevy versions the anti perc tube was hidden and not exposed above the top.
I am not sure.... the holes are big, but are also significantly offset from the main airflow. I suppose the hole could be covered but that was never my intention.
i think the real issues with the added holes is the chance of dirt getting in the air bleed. the added holes really are of no value. plugged/dirty air bleeds make the engine run poorly.
the primary booster actually has two air bleeds that influence low rpm operation. there should be a small brass air bleed on the side of the booster that runs in conjunction with the one on top of the booster.
