Sham’s heart was large, too. Another great horse. Did you notice how hard Sham was working his legs at the Belmont, though? Secretariat almost looked like he was strolling.
I read a few days ago that most race horses these days have Secretariat in their blood lines. I believe that Justify does, and American Pharoah (can never spell that word correctly, apologies!) was a great-great grandson. Seems his fillies do better than his colts, though.
Secretariat ran every 1/4 mile of all 3 races faster than the previous 1/4 mile. There was no quit in him.