I jsut emailed someone who asked how to do this. I think what I came up with is so briliant, I wanted to share it with the Stovebolt page. :)This is how I would do it. And I must tell you I think it is quite ingenious.
I would cut with a die grinder with a cut off wheel about an inch away from the corner windows on the five window cab. Make sure that you are on the flat area. So make it about an inch outside the rounded area. Let me make myself clear. We are talking a cut with a 1/32nd inch wide cut off wheel that is going around the outside of the corner windows up on the flat area about an inch or so. Make this a nice even cut using masking tape as a guide.
Then separate the inner metal panel from the five window cab. You could do that by grinding out the spot welds using a cut off wheel on a die grinder. Or drill them out with a spot weld driller. On the rear center window you could drill or grind them out on the outside being you will not be using that roof. On the bottom and sides at the door post you can do the same. Just make a cut up the post on the inside of the door jamb. Then from the inside where the headliner would go and down under the inner metal panel so that you can remove the metal panel WITH the outer window area that you previously cut out. Now, grind or drill the spot welds on the inside of the post to remove that metal off the inner panel.
You now should have the inner panel (actually, panels, it is made of three pieces with a seam going between each window) just as Chevy had made to install inside the cab, but with the ring of outer sheet metal around the corner windows.
DO NOT cut those spot welds around the corner windows, leave the ring of the outer skin on the. Now, make a pattern of the holes where you cut the corner windows out of the five window cab. Transfer the pattern to the three window cab and make a line ABOUT ONE INCH INSIDE OF IT. In other words, make the hole about one inch smaller around than the first one you cut. Now, remove the inner metal panels on the three window. This will be done all on the inside of the cab drilling or grinding so as to cut the welds without any damage of the back of the cab. Remember, you won't be using the panels so you can destroy that panel. Once it is out, trial fit the five window panel. When you have it fitting well you can screw it in or clamp it till you trim the holes around the windows. I suggest that you have it screwed in VERY well so it doesn't move. Trim the holes so they are about only 3/8" or so smaller than the piece around the outside of the quarter windows that you cut off the cab (that is still attached to the inner panel).
You now are ready to prepare the panel for welding. You can put a flange on the edge of the hole so the metal is flush, but I think that I would just let it stay the way it is, the inner panel will flex enough to take up the .030 inch or so in extra metal.
There you go, I think this would be an awesome way to get the job done.
