Rear Valance 67-69 Barracuda Dual Exhaust Cut Outs

I wouldn't say the dual cutouts were only "Formula S", since in 1969 there was also the "Cuda" package featuring the 340 engine.

And in 1967, only the 383-S had dual exhaust, and it had round cutouts and round tips. The 273 Commando, which could also be ordered with the Formula S package, had a very large single rectangular tip and cut-out, on the driver side only.

So the exhaust tips are associated with the engine choice option, not with the Formula S suspension package.

You can buy a dual cutout valance from Autobody Specialties and other suppliers.