I have not done it but have seen it. There was a magazine article a few months back about doing it in a car. I think it would be easier to just swap out the doors.
The frame for the vent window comes out along with the forward track for the big window. That leaves you the open space. I think but could be wrong that there might be some obstruction with the lower mount where the vent window frame bolts in the door. However it could be lower than the window when it is open. There is some sheet metal adjustments needed where the vent window latching hardware attached. This must be ground down as the big window will not clear it. You will also need window regulators that go with the pre-52 windows as they are not alike. The regulator mounting is the same on the door. The inside window moulding would have to be changed because there is a cut out on the 52 and up for the vent window frame.
Bill
