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

All 8 cylinder A body cars from 64 on until they went to front disc and big center hole in the 70's had 10 inch drums .Only 6 cylinder cars had 9's This doesn't mean you won't find 8 cylinder cars with 9's. People tend to use what ever they can when they need to get on the road and these cars all have history