Don't forget what we were stopping. I have mentioned before my Lotus 20 could out brake anything racing in 1965, including all the F1s. After Kevin Carrad & I had spent about 25 hours getting them set up perfectly the large Alfin drum brakes were as good as any set of discs of the day at stopping the car, & totally refused to fade. After all the 4.50x15" tyres did not have that much stopping power anyway. If my photo comes out you will easily see that brakes did not have all that much to do until designers suddenly discovered much wider tyres gave us lot more grip.