Here's a little follow up to your torque tube question:
I asked a GM Mechanic friend of mine what was the last GM car with an old fashioned torque tube rear axle. Without hesitation, he replied "1987 Chevette."
I looked it up in an old Motor's manual I had, Here is what I found.
It uses an intermediate drive shaft between the torque tube and the transmission, so it's not quite the same as a '60 Buick. But it's very similar to a traditional torque tube.
Not disputing your question/answer, just thought this was interesting.