This mod eliminates MOST of the throttle jerk but not ALL of it. I owned the car for 4 years before I noticed it still has a small amount of throttle jerk. The previous owner of my 240Z reduced throttle jerk from idle to take off by bending the upper arm of the "turnstyle" as seen in the attached pictures to a stair step shape effectively shortening it. This mod is no cost, possibly reversible and requires no welding, drilling or adding parts. The connecting rod with a nylon ball on both ends connecting between the turnstyle and the carb control shaft arm may not need adjusting or modifying as the new turnstyle connecting point for the nylon ball is both closer in one plane and further away in another which appear to cancel each other out. The PO for my car did this mod however the connecting rod on my car does not appear to have been modified. The first picture shows measurements of the bend in the upper turnstyle arm. The measurements on the ends of the arm are from the center of the pivot to the first bend and from the other end it is from the center of the nylon ball to the first bend from that end. This mod eases the throttle jerk by reducing "mechanical advantage". The carb butterfly opening is slower as the gas pedal is first depressed off idle compared to the stock arrangement.
To the PO who did this throttle fix a tip of the hat and a moment of silence as I am aware he has passed on.