There is no need for the kick down rod or cable they make now. Not only does it help to clean up around the carb it makes it easier to swap different carbs fast.
Problem with that kick down rod / cable is sometimes the engine makes great power at half throttle. Like using a 750 Holley on a built motor. The trans pressure might not be quite up enough to handle the engine power. My tranny guy said nothing happens til after a while but you might get 2 or 3 years out of the trans instead of 5 to 7 years.
Now the 727 trans is one tough tranny. I'm using the weaker 904 and my tranny guy felt it was needed after driving my car years back. He said its hard to set the kick down right and still allow full throttle openings. Now I understand the cable has something were its possible to set it up right but I kept my manual valve body.
A reverse body allows you to slam it in to 3rd gear without fear of going to neutral or even reverse. The faster the car the more useful that can be.
It can be a pain in city stop and go driving. Just depends on how you use the car and if your gf or worst yet your kid uses it, he he. The tranny outfits do make HP street valve bodies that allow automatic shifts and with a cable set up might be worth looking in to.