727 part throttle down shift questions ?

I thought that PT KD valve started on V8s, in 71. I think the slanty got it a little earlier. The slanty valve can be retrofitted down to 67 for sure. After that I don't know. This I know; that any TF VB fits any TF case, down to 1967,at least.That is to say;I know it will physically bolt on. But I can't say what works with what.

There was a guy on FABO not to long ago, that was having issues with his tranny He had a late VB on his pre 67 case. I don't recall the issue but I'm pretty sure it wasn't a VB issue. Pretty sure, is not FOR SURE.