Where does the S badge go?

For a 1967 with the right fender pentastar removed. You will have two holes one center of pentastar the large hole and a small hole top of P-star.
Take a straight edge from the big hole using small hole to center draw a line or mark from the center of the P-star to bottom FS emblem stud is 4-1/2” and 6” exactly to top stud. which should put the bottom of the emblem circle to the bottom ridge at 1-3/8 in”. Make a template from the right fender and do the left fender.

It is easiest to remove the P-star emblem and attach the Formula-s emblem by removing the two bolts holding the fender dog leg on and the bolt on the rear fender lip. Doing this will allow you to pull the bottom of the fender out and reach up from under to install the nuts as well as remove without damaging the P-star emblem