What's the diference between a shift kit and a valve body?

 

A shift kit modifies an existing valve body to make make it shift much firmer.
Every tranny has a valve body. A shift kit is just a mod to a valve body.

 

yep......the shift kit reprogrames the trans and changes pressure in the body

 

I think he's talking about manual valve body & shift kit.
With a manual valve body the tranny will not shift automatically. Which ever gear you have it in. It will stay till you manually shift it. Think of it as a clutchless 3 or 4 speed.