Late shifts after new torque converter.

Transgo shift kits are good, pumps in park and neutral.

Sounds like the kickdown needs to be set up from scratch again, especially with that cable setup. Oldkimmer is good at this.

Basically you want the kickdown pressure arm full on, at the same time the throttle is wide open.

But again Oldkimmer knows best. Can take some tweeking to get it just where you want it when you get it close.