[TERRYP]

I do not know just what cars I got my belt drives from, but virtually all GM cars of the late 70's up had them. What I went for is cars with tall windows, as many cars do not have enough travel up/down for our trucks. The big trick is to get your old regulators working smoothly, then the lifting point will be way at the back of the window. You also have to straighten out the belt tracks, and that takes some time, and I made a special tool to slide along the track slot to space the slot evenly. On my 68, I threw out the whole regulator, and placed the lift point near the center of gravity of the glass, with a little bias towards the glass tipping foreward. This worked great on the passenger side, but I could not get the driver's side to work without using the regulator to hold the glass level.
The auto up feature is handled by a black box not in the door, works on current sensing, I think, but I have never been able to find such a box under the dash of the caddy's etc, that have the feature. I'm going up to Everett, WA this week, and plan to hit the junk yards, and the auto up boxes are one of the things I'm looking for.