Again, that sounds like a late opening power valve. You get a giant hole in the fuel curve and nothing will cover that up.
I also had a carb that had annular boosters that I could never get the hole in the fuel curve fixed.
I finally junked it. Most carb guys wouldn't even take it on.
FWIW, if it's not a PV issue (either opening timing or power valve channel restriction or both) it could also be a booster issue. It could be getting on the booster too late. And you are killing it with a long pump shot. Or, it could be getting on the booster too late. And no pump shot will fix it.
