I was able to install a similar kit into my 69 G.S. 400 without removing the door. I was able to drill out the hole from inside. I'm not sure if the vent window would change that since my 69 didn't have vents. I have had similar problems with the windows sticking in the down position. I have not resolved that yet, the car is in a full restoration so when I reinstall the glass I will examine that closer for binding issues. I know its not the motors.
