Vacuum Secondaries

For what it’s worth, and a static test has the car seats and you hover over the top of the carburetor opening throttle wide, the secondaries would be challenged to be opened. As you’re traveling down the road the vacuum secondary carburetor should be a smooth opening of the secondary side. The kick! That you mention comes from the downshift of the transmission.

The vacuum pod contains a spring which you can swap out for a lighter or heavier spring.