Hopefully one of you can help me - the window closes to less then a quarter inch from the t-top weatherstrip - have had the door apart and checked the gears several times just can't get the window to rise that last bit.  Is it possible to adjust down the t-top weatherstrip?  If so how?

My self, I've never seen a way to move it, but what I would do is to measure the amount the window raises on each door, I suspect some problem with the regulator, motor, etc.

Dave

Check the window stops (When the window goes up it hits 2 stops that can be loosened and reset). They may need to be adjusted up a little.

The "stops" that Redwingvette mentions are in the vertical rails in which the rollers go up and down.  They are at the top of the rails and each is held in with about a 7/16 hex bolt.  If you have the door panels off, it's a VERY easy adjustment.  Here's how I did it:

1) loosen stops, raise them up out of the way of the rollers tighten just enough to hold them up there.

2) Shut the door and raise the window all the way up against the weatherstrip.

3) loosen the stops, bring them down until they rest on top of the rollers and tighten a little.

4) lower the window

5) mark the location of each stop, then lower each just a little (maybe 1/16 - 1/8 of an inch and tighten.  If you don't drop them down a bit, it will probably make it hard to shut the door and, when the window is up when you shut the door it may to be too high and catch on the little metal tab at the top of the windshield pillar and not let the window rest against the weatherstrip properly.  If you get them too low, you'll obviously have water or air leaks.  (of course, it's a C3 Vette, so you're not going to totally eliminate that!) 

6) test it out and raise/lower the stops until the window just clears the metal tab on the pillar when shutting the door with the window up and you should be good to go.

Good luck!