Kickdown linkage

yes it is holding the kick down linkage to far back and is just a bit to long.
The slid hole in your kick down rod up by the carb can be drilled out to make it move forward some, Make sure it is not hiting anything, But it sounds like the presure valve arm at the transmission is being held to far back just a bit. Make sure you have a soft return spring so the kick down linkage can return back to drive location.
I will see if I can get a picture to day to help you out.