window rubber

Howdy again. I have an idea for my 54 Ford, but I don't know if I can make it happen with available market stuff.

I want to yank the back glass and fill it in with a steel panel that has a custom rear windshield shape cut into it. I can make the panel, cut the shape in the middle of it, make the flanges around the cut-out for glass to sit inside of...but I need some way to seal it. I thought of using an old, but still good, station wagon window gasket I had laying around...until I realized it's a factory GM part that is formed to a matching shape channel...kinda' like trying to get a rope seal to work on a tongue and groove rail.

Is there any rubber company out there that sells lengths of window rubber that will fit over a basic 90 degree flange? And this wouldn't be a pre-made shape..I'd have to connect one end of the length to the other. How do you get the two butting ends of the seal not to leak where they connect?

You might check J C Whitney - they have different configurations and one might bee what you are looking for. Also check Restoration Specialities in PA. Thay might have something.