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

My 66 Formula S. 150 mph speedo, factory tach, (working WITH electronic ignition, not an easy feat). The 4 bbl cars had 10.5:1 compression solid lifters, the two bbl cars were 9.0:1. Mine has the "racing brake package", seems pretty rare. The rear drums are pretty much unobtanium, fortunately mine are good. It has Kelsey Hayes 4 piston front calipers but according to the fender tag didn't come with them. I believe the Formula S cars all had console shifters but don't hold me to that.

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