Yes, they will open fully without hitting the stock flag mirrors.

the side mirrors aren't even close, so you can open it as much as you want.
However: The mechanism of the vent windows only allows to open them 90 degrees.

Quick question as I gather parts to do this myself. Are the clips that hold the vent window posts different from side-to-side? The vent windows I bought came without them, and the replacement clips I bought were identical to one another.

http://forums.pelicanparts.com/uploa...1618947654.jpg

http://forums.pelicanparts.com/uploa...1618947654.jpg

http://forums.pelicanparts.com/uploa...1618947654.jpg

I have a set of these from a 74 targa silver trim that I'd love to trade for a fixed set new seals including the corner piece

RDM, I'm pretty sure they are different side to side. The collar on the clip is supposed to be on the top side of the pivot pin, closest to the window frame. Take a close look at the picture below from my restoration of my vent windows.

http://forums.pelicanparts.com/uploa...1619185943.JPG