Driving without throttle linkage

Related question/ been a while since I have been inside of one
On a 727 that needs overhauled because it was run with kickdown disconnected, what usually "goes first" within? How "bad" of a rebuild would be needed?
Basically clutches steels and seals or does it tear something else up as well?

My son just bought back an old truck of mine that my cousin did "no favors" to. One of the first things we saw upon opening up the hood was the link from the carb to the bell crank laying on the manifold. Rumor has it, he had his dad did head gaskets on it a few years ago. I'm guessing it's been run like that since the head gasket job. Idiots.
My son bought it back to hopefully harvest the motor and trans for another project he is working on. But it appears we will be tearing the trans apart before it goes in.