Kip,
I have done this and can tell you how to do it.
Last winter, I chopped my Chevy Coupe and eliminated the vent windows. I have a buddy who has a Streetrod '40 Chevy Coupe with one piece glass also.
You have to buy an extension to support the longer glass you'll be using available from several after-market rod shops. Try Yearwood's or Butch's Rod Shop. After taking the old vent window out, you'll have to do a very simple but delicate maneuver. Find the apex of the curve(where the the vent window met the door glass) and push firmly but carefully until the outside door area where the glass goes is straight. Make sure the door glass support(in the door) has been removed. The inner window trim will have to be ground down a little to make room for the straight glass.
Believe it or not, this will work! All of the body guys I have talked to said it wouldn't work, but amazingly, it does. If you go past straight, you'll have to use a pry bar to straighten it out.
By installing electric windows with a new mechanism, everything will work smoothly and will be fine.
Another simplier way to achieve a one piece window look but retain the vent too, is this solution. On my Chevy, I installed a new 1-piece "U" channel and went completely around the whole window. I removed the vent window and top half of the mechanism. I glued 2 rigid "C" channels together and cemented one side to a newly cut vent glass. I had a glass shop do the glass so everything fits. Once you slip the vent window in place, the window glass can roll up nicely using the glued on "H" channel. When you drive or park at a show, you roll down the window, slip out the glass, and you have no vent window! You can also drive with it out too, but I like the vent window in as it it buffets the air out of your face.
If you need photos on this, just email me and I will send you the photos. Good Luck!
RapRap
1940 ChoppedChevyCoupe
