[rdorman]

What I have seen recommended and done with sucess..... Stand on it in one of the upper gears at the minimum RPM you plan on full throttle use. If the motor is pulling well and then all of a sudden pulls REALLY hard at high RPM, like a turbo kicking in, generally your secondaries have yet to open(sure, could be other things!). Go to a lighter spring. Try again. Keep doing this until the car bogs or falls on its face and takes time to recover. Go back to the previous spring and test drive. Keep the spring the same in both carbs.

Rick