Windshield seal needed

You might see if you can just get some sealant around what you have. I have a 67 that had a bit of a leak and I just got some windshield sealer from the local parts store and put it in between the gasket and window frame (the top corners looked like the culprit on mine). Looks like it may have stopped it or at least slowed it down quite a bit. I think a tube of it was only a few bucks, so it might be worth a try if you can't find a gasket. You can get a later model gasket, but you won't have the lock strip or the clips on the windows frame to put in later model trim unless you weld them on.