[fleetsidelarry]

DanSaco, maybe I missed something above so correct me if I did.

You're asking about converter lockup/unlock NOT kickdown (i.e. shifting from 4th down to 3rd), right?

First, my understanding is that cable adjustment doesn't control lockup. It IS critical, as others have noted and you may have known already, to proper control of the internal pressures and shifting.

Just to clarify, when you say "factory linkage bracket" are you referring to the linkage on the side of the carburetor? Forgive me if you already know but I ask because some people think the bracket holding the tv cable is what needs changing (from one of your posts: "Not 100%, I've adjusted it a couple times to try to get it as good as I can. I'm going to buy the aftermarket bracket to move the back end of it to try to make it better. But that's been in the back of my head too") but, in fact, it is the one on the side of the carb. the Edelbrock geometry isn't correct and you can't properly adjust the cable without fixing it.

I believe the Bowtie kit will require you to pull the pan to install a spring, mine did. Maybe they sell just the geometry corrector. other sources do

Don't know exactly what you did to test it when you hooked manifold vacuum to it but the way the vacuum switch operates is to unlock the converter when vacuum drops during rapid throttle application by breaking the electrical circuit to the converter.