Agree that Blades was faster than Brown, but “world class speed”? Now, there’s a phrase that’s overused to describe football players. On today’s rubberized carpets...I think Blades would’ve run 10.35-10.45 (I want to say he ran 9.4 at the county meet; 9.5 in the prelims of districts and then false started the finals his senior year). And that’s close, especially in high school. But, it’s not “world class”
If you’re talking about the 100m, to me...
World Class < 10.15 (in the 80’s...world class was probably a full tenth slower, maybe more)
National Class < 10.30