I did the same thing with my 66 GT when the brakes were stock. A 1/8 mileDefinitely agree. I never tracked my 65 but I gave it some seriously competitive street use. While cold, the Kelsey Hayes calipers and factory rotors stopped much better than one might expect, but I over heated them several times. Some serious fade.
offramp was not adequate to stop from whatever asinine speed I was going.
So I upgraded to the B302 Trans Am fronts. Problem solved.
ex-Global West GM