'65 Formula S always have 10" inch drums on front or some had 9"?

My first 65 had 9's and a V8 per the VIN. I bought it with a 340 in it already and those 9's were downright scary. "S" had to have 10's as that was called out in the "S" package. The 273/4 did not make it an "S" either.