As the earlier windows were thicker, they won't fit the smaller window channels of the '52-and-up trucks. Therefore, in order to make the swap to the early style windows, one needs to come up on some early style window channels (early style aftermarket channels don't exist, at least not yet) or fabricate your own. Keith at Classic did just that. He started with the rear channel: First he measured the side flanges on the stock channel and then measured the width of the new '47-51 molding. Next, he took a strip of 18-gauge sheetmetal, accommodating his measurements, and traced the width of the new window molding onto the strip down the middle, leaving the edges the exact height of the stock window flanges.