Are the 1968 conv top frames the same as 1966 frames
Wow. I never posted A question on this site that nobody could answer.
I can't answer your question as I've never owned a controvertible (except a 59 VW Dune Buggy), but I will direct you to this forum's library for you to do some research using "Ford Car Parts" (aka MPC), the 1975 edition. There are downloadable links posted in every year. You might also invest in a set of Mustang Assembly Manuals for your car's year.
Jim