Modern gas isn't ideal for carb's. Lowering the floats 4 flats may do the trick. Taller vents or connecting them with a hose with holes on top could help as well. Is the spacer wood or phelonic?
Not sure of the construction. I haven't seen it in person since the addition was made.
When you say 4 flats, do you mean turning the bolts?
Brian Hobaugh SCCA National Tour June 2014
First Hemi 'Cuda Convertible Ever Built
Short clips: Goodguys Pleasanton autocross and pit videos
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