Carb tuning

Hey guys as some of you may have helped me a while back i got the car running and driving have a holley carb on it thing runs out great but if i am cruising as well as sitting at a stop and mash it to the floor it cuts out for a second then kicks in and takes off i checked the vacumm and put a smaller power valve in it and it helped alot then put a bigger squirter in it and adjusted the secondaries and again helped out alot but it is still doing it ever so slightly..any ideas. Tricks. Tips?? Anything helps

its a holley double pumper 650 cfm