need some trans help..tf3 won't upshift

I have installed the TF-2 kit in pre 71 valve bodies with no problems. In fact I have a 69 VB in my Cuda now and it works fine except naturally it has no part throttle kick down but it doesn't bother me since my 408 has an abundance of torque. One issue I ran into a long time ago is not to grind down the throttle valve as far as they say or some don't want to kick down like they should. In a case like PoisonDart describes I wonder if there's maybe just wear in the VB casting and of valves causing issues. Being 70 valve bodies are 44 yrs. old it's a possibility

SB75 since your kit is the TF-3 kit that converts it to a manual valve body I wouldn't think it'd make much difference which year VB you use.