The snaps work well. One at the top so the strap doesn't fall in, and one at the bottom the material stretches (very little) but mine holds the window up tight. I put it down on the return road every pass, 300 passes. You can see the left side is down, the right side is up. The shiny spot on the right between the door handle and vent is the down snap.
Doug

Do you have a full pic of your car? Just trying to see how that color looks over the whole car,not sure on the color on my 64 and not saying I would do your color,love it, but just getting ideas of shades because some just don't work on a Savoy. Hope that came out right. LOL

Here you go. As you see it depends on if it's in the sun.
Doug

While I am no expert, I don't believe that the original 68 SS cars had buckles on the window lift belts. Here is a link to Mancini's old car that is at Mecum now. There are a couple of pics of the interior there. No buckles on the window lift belts on that Dart.

Besides, I tried the buckle. First, it really doesn't do a good job of pulling the window up after the belt goes around all those corners. Second, it is hard on the paint where the belt rubs. And lastly,that buckle flopping around the top of the door when the window is down, isn't cool.

The elastic and a snap is just a better way to go, in my opinion.