Got Shell 93 Octane and now barely idles 1973 Dart 340

Yeah that's the adapter to use but I would use long studs in the original locations and use the inner pattern on the carb. That should provide less distortion of the adapter and better clamping of the gaskets.

That is what I was thinking, but why did the previous owner RTV two gaskets on the intake side then the adapter and a thin gasket to the carb. The previous owner air cleaner was so high it was gouging into the underside of the hood. I changed to to a lower profile because of that.