FYI... many parts that were supplied by 3rd parties (sender floats for example) are very common between cars of the same decade. So sometimes a 65-70s mustang might be the same and more plentiful being one of the chosen.
There’s a National Parts Depot near me and I used a float from a Mustang on my Belvedere. The only issue is that it’s a little shorter than the original but it works fine for my application.