I have a '66 Grand Prix with the vacuum trunk release. It also has ATC A/C. This might affect things???
My car has TWO Vacuum tank canisters. One larger unit is located on the top of the left hand side (Your drivers side), inner fender. This unit appears to be associated with the ATC A/C.
There is another, smaller tank located up above the glove box under the dash top. From memory, it is about the same size as yours seem to be.
HOWEVER, I need to stress that I have never really followed through how all the vacuum lines are interconnected. I have vague memories from when I have been under there that the smaller tank is connected via a "T" piece into main vacuum line feeding the ATC controls. That might be a bit wrong so please don't take that as gospel.
Ian
