Why is it so hard to get good advice !!???
The secondary's might not be coming in soon enough and it's leaning out.
I would run at least a 950 cfm carb with mechanical secondary's.
A race carb with no choke for sure.--better fuel curve--
A race fuel curve is richer over all.
If your running a duel plain intake i would get a 1050 cfm carb.
PROFORM / QUICK FUEL / THE NEW HOLLEY......