New Carb problems

That return spring under all the linkage is something I have not ntoiced on other cars and looks like it may be the cause of some interfearance. The other one on the outboard side I also never seen.
I would run a double spring pulling the carbs arm foward and delate the two pulling the carbs arm from the bottom rearward.

One other issue is the pumpshot arm should be moved from the outboard slot in the pumps arm lever to the closer one as to help deliver a larger and quicker pump shot when hitting the gas pedal.

You should grab the thottle lever adapter and proper stud for the throttle cable and kickdown linkages. What you have looks very small and is scary to look at. Looks weak and flimsy, possible brakage.

Also, is this cars engine fully warmed up and is the choke fully off when you try to accel. If the choke is not fully open, it will lock out the secondaries.