If your talking about the final tack rail that's below the body by the top well that stay in place and doesn't move. It's been 24 years since I did my top. I followed an article out of a hot rod mag. on how to install a top. Since then with the internet there should be plenty of articles and you tube videos out there. It doesn't even have to for a gm car as most tops fasten the same way. The article I followed was done on a ford Fairlane. Just a lot of measurements, double checking and take your time. Don't rip the old top off. Pull each staple out one at a time carefully so you don't mess up the cork tack strip. Use nickel or Stainless steel staples so you don't have rust streaks. Get a top with glass window as that's what was original. Plastic is a pain. New guide wires on the sides and new pads. Critical to get centered perfectly as some tops don't have more than 1/8" on each side. If your top now goes up fine don't mess with any adjustment and if you want to clean and paint it take it out as an assembly, leave everything together sand any rust or bare spots , then paint.
Do not take it apart or you will have one heck of a time getting it adjusted!
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