What "makes" a 66 Barracuda a Formula S ??

junkyardhero said
on the fender tag AB 32 and F 7

HD suspension (sway bar) and tach is part of the package.

i believe discs were optional.

This. @junkyardhero got it. 273 HP (10.5:1 pistons, stronger cam, 4 bbl. Sway bar, tach.

I have an original brochure at home with the list. If I remember (I'm three years older than my 66 Barracuda), I'll attach a picture of the list.