There is a bead along the front edge of the top....a rolled trim piece, part of the top. If it gets tucked under and seals against the header, you get more noise. That bead needs to be pulled forward, so it lays flat on the windshield frame with the top latched. Sometimes they want to curl up and get between the windshield frame and top header, and seal unevenly. Happens on my '67. Much quieter if I take the time to pull the trim bead out and forward as I latch the top...sometimes takes a helper pulling on the pass side while I pull on the driver's side.
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Jeff 
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