You guys have always had the answers to my questions, so here I am once again.

I recently bought a Quadrajet off a 70 Buick 455. This is going into my Skylark convertible project. I am also upgrading to an overdrive transmission.

The problem is that this piece as denoted by the black arrow won't work with the TV cable.

Is it possible to swap a base plate from another Quadrajet onto my current one?

yes

Does it matter what year the base plate is from or should I try to get something close to the same year?

If the base plate has all the same passages, and they all line up, it's good to go. It is likely that you will need one from a similar year.

It would be only a little more work to swipe an auto trans throttle shaft (with proper automatic-style throttle arm) out of another QJet. I wouldn't bet my life that the baseplate from a different carb would be a perfect match with the vacuum passages and such in your current carb. Just grind/cut off the exposed threads of the throttle shaft screws before you try to remove them or you'll butcher the screws and the threads trying to get them out.

Now you mention a "TV cable". Should I assume this is a 700R-4 or 200-4R trans? If so, the shaft you REALLY want would be a from a later computer controlled QJet that had the same trans behind it (3rd Gen automatic Camaro with 700R-4, for instance). The trans cab;e stud is in a slightly different place for later cars that used a trans with a TV cable than earlier QJets backed by a 3-speed TH-350 trans with a kickdown cable.

All this assumes that is a QJet with the round choke housing built into the side of the carb. Real early QJets with a divorced choke assembly used a different primary throttle shaft than any of the later ones with the round choke housing on the side.

If you end up swapping baseplates, do as others have said and really look close at the vacuum passages, I bought a q-jet a few years back from SMI (Sean Murphy Induction) and it wasn't acting right,I found that at an idle it wasn't pulling the power valve down?? I called him up and he said to send it back and he would check it out, I told him I would look at it a little better before I sent it back, I took it apart and compared it with another Q-jet and found the vacuum passage that supplies vacuum to the power piston was not drilled so there was no way for it to be closed at idle thus causing it to be pig rich, I sized up the hole in my origional baseplate and drilled it out and the carb was fine after that.