I'm referring to the kickdown lever on the outside of the trans. It has to be all the way back when the carb is all the way open. If you stray from that adjustment, then the arm will never go all the way back; lowering the pressure to the shift, or the carb won't be allowed to open all the way; hurting performance. You don't "fiddle" with adjusting that to relieve pressure on the kd as jpar suggested because it will lower the shift pressure and burn the band and 3rd gear clutch. (of course he'll deny saying that) Incompatible linkage can cause a late or early shift. The ratio between the carb, kd arm, and sometimes bellcrank has to be such that the initial arc of the kd arm is timed properly. Summary; if the kd arm does not go all the way back at wide open throttle; friction material will burn.