Emily, make sure you Google search Secretariat, racing statistics... also, I just found lots of information at this link
Kentucky Derby 2007 Betting Horse Racing Betting News - Secretariat : The Triple Crown Winner you have to read the statistics and look in the parenthesis, it tells you which wins were record breakers... you have to do the foot work yourself, count them up.
Fyi, there are over 7,000 websites that info on this topic, I doubt you've been to EVERY website... "every" and "never" are words that just don't work very well. Take care, good luck on your project... what IS the project by the way? Jane in California