Part throttle kickdown source?

[Bronzedodge]

I'm looking for some junkyard valve body parts.  Years back there was a magazine article on adding part throttle kickdown parts to the earlier valve bodies that do not have it.  I've pulled the pan on a 72 and a 73 904, neither one had it.  Anyone know for sure what trans had this? 

[John_Kunkel]

In the early years only the /6 904 had it, from '71-on it was hit-and-miss but usually always on the /6 trans.

[Bronzedodge]

Thank You, John.