I started betting in 1953 though still legally a bit young.
I grew up in the 1940s and was in and around older raing families
in my youth.
One thing was certain. Those 1940s horses all had one theme in common. They were off the pace runners who deployed a stratgey
of holding back early in a race and then turning on a big brush to win. Assault, Citation, Count Fleet Whirlaway all ran that way for the most part.
Even without looking at the times those 40s horses set
every one of them will have a serious problem with a speed freak of Seattle Slew`s caliber.
Running styles do back it up. If they gave Slew a soft lead they will get BEATEN.
Honestly I have seen 20,00 races in 50 years and horses who get loose on the lead with Slews finishing kick have seldon lost.
Seen too much in 53 years.
All of the 70s tops horses would club the 40s horses