You are pointing to idle air bleeds. The size of the holes in these is not "fixed" and varies from carb to carb. If the holes in the parts you pirated from the 2-bbl are much smaller than what you need to match the rest of the idle calibration (down channel restriction, idle tube, lower idle bleed), the idle will be rich. If they are too large, the idle circuit is likely too lean.
Can you kill the engine by running in the idle screws? How much of the transfer slot is exposed at your idle throttle plate setting? Do you see fuel dripping from the boosters when you look down the carb at idle?
My suggestion would be to pull apart the carb, and document the sizes of all metering orfices. Compare to a "recipe" in Cliff's book, and adjust accordingly.