To add to that excellent thread that Will posted from Michael Yount on his 240 windshield replacement project, here’s some additional excellent info from Dave Barton’s site
https://www.240turbo.com/240windshield.html

Additionally, here’s a link from that thread to Art’s notes on windshield replacement
http://cleanflametrap.com/windshield.html#LTFGW

Being aware of the issues and being able to provide info on substituting the later windshield gaskets in place of the original trimmed windshields may help encourage a friendly glass shop or mobile installer to take on the job. Especially interesting is the different width gaskets that can be used to hide paint lines.

Be extra prepared for rust at the pinch weld seams and rather than just letting them goop it over as some installers might do that you get them to pause the job and allow you to do a proper POR rust fix before they continue. With that in mind, many elect to remove the old windshield on their own and do all the prep work. Many articles here and elsewhere on getting the windshield out. It can be a bit of a messy undertaking and a mobile glass installer can make quicker work of it if you don’t mind paying for the privilege.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now