With the linkage disconnected at the carb you should be able to pull the kickdown lever on the trans fully forward so that when the linkage is reinstalled on the carb stud it will be at the rear portion of the slot, as shown in the previous post. The spring should exert forward pressure to keep the linkage tight against the carb stud so that when the throttle is opened the linkage moves and pushes the kickdown lever on the trans to the rear. These adjustments are done at curb idle (not fast idle).

If the trans is an 80's 727 they have a problem with the front clutch pack seal failing which causes a late 2-3 upshift. This can be detected in the car by pulling the valve body and doing an air test.