You know I’d always thought that a/c was standard on all 66’s. It was air conditioned by heat through the right and left vents, plus the power of opening vent windows. Sure it wasn’t cooled air but it was conditioned by the smell of a 289 HiPo with the additional of musical notes of solid lifters
Beside that I never saw an actual Shelby with “factory A/C”. Hang on units yes, most were Sears or some other aftermarket units
Would love to see photos of any Ford units on a 66 Shelby including the bottom pulley and belt routing with idlers and adjustment pulley