I would remove the striker and try closing the door with the window down to meet the qtr. panel flush. If you can do that with only minimal effort and your door fits good then your striker adjustment is off. I would bet it's in the weatherstrip as that is a real pain on the 69 & 70 models. The striker can be adjusted slightly up or down or in or out. You do not want the striker to catch on the latch and pull your door up or down, it's only purpose is to latch the door. If your door sits further in than the quarter panel, the striker is in too far. If the door glass is down and it shuts good the problem is in the glass adjustment or the roof rail weatherstrip. This is a real bear getting all this lined up and fitting correct...good luck!