Yes, I agree it will not alter your current problem, just something else to address.
I can't for the life of me work out why the IFRs ended up above the fuel level.
Every other carb I know has ALL fuel jets below fuel level, and all air above, makes sense.
The trouble with the larger Holleys is the same down leg booster is used across carbs from 650 to 1050.
Can you see the signal strength at the main well must be not as good on the larger carbs.
I like annular boosters for that reason, they sacrifice a little maximum airflow for a stronger signal.
Remember, the carb won't flow 850 until 1.5 inches of manifold vacuum occurs, if ever.
Have a look at how Troy from TMP carbs does his.
http://www.tmpcarbs.net/carb_gallery_p1.html
Virtually maximum venturi diameter, even egg shaped, with annular boosters.
Gary