I'm no expert, but from my understanding the spring helps the cable to return properly. That's the main issue with most aftermarket setups. This is to help with shifts under normal operation at mid to low rpm. If you are having full throttle late shifts, could be a governor issue or the cable is out of adjustment. Hope this helps!

Thank you for your comment! The cable has a large amount of adjustment to compensate for this, if you would like to adjust the throw in this way. What I video'd was how I had mine setup as an example. I will reiterate, however, this same setup is sold by a reputable company in the Mopar community with their own special plate to adapt this same cable to the carburetor for 3 times the price. All I did was use this plate for inspiration to come up with my own way of connecting this cable. In addition, this cable was used by Chrysler on the evolution of the 727/904 the 42RH/46RH which still used a similar valve body and the same method of applying pressure to the kickdown lever to control shifts. So if there was an issue of moving the kickdown lever in time with the throttle it would have reared its head here, in my opinion. If someone reading this has concerns, I would reach out to your local transmission shop for professional advice.

@@opietinkers yeah it might be fine. I just know that there is more slack in that old mechanical linkage. Maybe not as much as I initially said. I’m trying to rig one up for a 727 to a gen 3 hemi. With the throttle body still. So I’m just researching stuff

​@@re-geargarage I get what you are saying, I played around with the kick-down arm a bit through and the first 1/8th to a 1/4 of travel there is honestly very little resistance. So I doubt the line pressure is fluctuating much with those inputs. Would be interesting to see with a gauge on the transmission though. I just don't have one of those. Also, to point you in some direction for your project I noticed BBK makes a throttle body that does look like it has a kick-down stud on it. It isn't cheap, but may help with your problem. I have also heard of people welding a bracket to their throttle pedals and attaching the trans kick-down there for these sorts of applications. Usually a Lokar style cable is used for these situations because it is easy to mod the cable end that normally attaches to the carburetor to work in this spot. I would also check out the Hemi Half swap on Vice Grip garage. His truck runs a full Hemi swap that I believe is cable, not sensor, controlled, you may find some inspiration there. Good Luck!