Bob,

I believe '72 was the first year with a thermal timer. '71 lays responsibility for the CSV on the ECU and an additional relay.

In either version, the CSV is powered from the starter solenoid circuit, so it does nothing when the starter is not engaged. The ECU or thermal timer only enable it. A non-functioning CSV cannot cause the car to stall.

On cars that do have the timer, I've seen it in two locations: 1) in place of the block drain, which is in contact with the coolant, and 2) in the larger threaded hole at the extreme right rear top of the block, which is not in contact with the coolant. I think those are D-jet and K-jet versions, respectively, but wouldn't state that as a fact.