is that from a dead stop, roll or brought up on the converter? have you stayed in it long enough to see if it comes around? mine does that too. you have the same problem i do, to much carb. there just isnt enough vacuum signal coming from the slant to pull the fuel through the boosters right away. you could make it up by trying the 50cc accelerator pump and playing with the pissers and the accelerator pump cams. or im sure you dont want to hear this, go for a smaller carb. cfm requirements dont change because of the turbo. the 390 is still the go to carb. if i could have found one cheap i would have run one. they do make them in the double pumper configuration, they are popular/required in a lot of circle track racing. i have a 650 on now, i have a 600 sitting in my garage waiting on the hangar18 mods. im hoping the smaller venturis will make better use of the limited vacuum signal.
