Glad to hear you got an improvement, but lets be honest. The carbs are over 40 years old. Your linkage ball and caps are worn, and mostly the bushigns on the throttle shafts of your carbs are probably worn as well. All of this adds up so a sticking throttle right at initial throttle application. I had the EXACT same problem on my car and it made taking off smoothly impossible. But I found the sure fire solution.

I sent my carbs off to Ztherapy, who removes the worn bushings and replaces them with bearings! Hey also rebuild all the linkages on the carbs and CAD plate them to shiney new.

When I sent them off, they were a sticky mess, when I got them back, without adjusting a thing, they were spot on perfect. Smooth gas pedal application, and felt like driving a new car.

I am glad you got most of it fixed, but the truth is the bushigns in your carbs are probably worn a bit.

I really want to order a set of rebuild 4 screws from Ztherapy, but they don't seem to respond to people outside the US