Actually, only 1 horse has ever achieved the "Grand Slam". American Pharoah. The Breeder's Cup Classic didn't exist back when the prior Triple Crown winners were around. It's a very new title.
Apparently, I am being a pedant horse racing history buff on the internet today.
You could be right this info was on the internet and in haste misread it also mad mistake of looking it up on iPhone (small screen)
