[truckster]

I would say a 67-72 Chevy or GMC truck is not the vehicle to learn on when it comes to changing a windshield. Their design makes it a little challenging even for experienced installers.

If you decide to replace it yourself using your parts truck glass, use a utility knife to cut the windshield gasket all the way around the inside, right next to the pinchweld.

Install the gasket on the windshield. If you have chrome trim, it has to go in the rubber before the rubber goes on the truck. Use some masking tape to hold the rubber on the glass.

You'll need a length of 3/16 or 1/4 inch hollow braid nylon rope. Lay the rope in the pinchweld groove on the rubber, starting with the center of the rope in the center of the bottom of the windshield. Cross the rope in the center at the top.

Next you're going to need a helper. Two is even better, because you're going to install the TOP of windshield first. With your helpers holding the windshield in place and putting gentle pressure against it, you'll start pulling the rope at roughly a 90 degree angle to the glass, so that you pull the rubber over the pinchweld as you pull out the rope. Use glass cleaner or water with some dish soap to lubricate the rubber as it passes over the pinchweld. Easy does it on the top corners; that's where these like to break. Once you're past the corners, it's pretty simple from there, if you've centered the windshield and managed not to lose any of the chrome pieces.

One more word of caution. Don't under any circumstances, use silicone to try to seal your windshield. It might work temporarily, but it will cause more problems in the long run. Butyl rubber sealant is the correct sealant, but if you can't find that, I'd use 3M's black super weatherstrip adhesive.

Good luck in any case.