noobie.

Not all Formula S cars were 383s, in fact there were not that many made.
The vin will start with BH29_7
BH29 is Barracuda fastback, the next letter will be the engine code. An H would be a 383. The 7 is for 1967.
Take a pic of the fender tag and post it, you want to see a 7 under the F for Formula S.