Don't feel pregnant, there is a lot of info on these threads but the only thing I actually see/read anywhere was either they put a piece of foam as a spacer behind the top of the window channel, or bent out the outside surface of where the outer felt attaches before installing glass and felt.
http://www.67-72chevytrucks.com/vboa...d.php?t=686833
http://67-72chevytrucks.com/vboard/s...d.php?t=707217