Enzo-
I finally figured out the linkage on my IDAs-I got a new throttle lever and drilled a hole in it about 5mm closer to the shaft axis and installed it on the passenger side. Now the carbs pull the same amount of vacuum at idle and above. I never doubted you were right; I just had a real hard time finding where the linkage needed to be adjusted and by how much.
Thanks-
You and Paula are the greatest!
Tim Black
tblackgt350@mindspring.com