Old window glass & new doors

[allons]

I've got a real pain of a problem. My truck is a '72 C10 and I'm doing a frame off resto/mod. I had to trash the original doors but I saved the glass and rebuilt the vents. The new doors are aftermarket with all new regulators, etc. The problem is the original glass will not roll all the way up. The glass jams about 3/4 of an inch from the top . . . on both doors.

Has anybody got a way out for this problem? Thanks!