There are several horse racing libraries that allow the public to use them. Across from SA is the Burke Library and the staff is very nice. Keeneland Library on the grounds .... same. The National Museum of Racing at Saratoga has them, but I am not sure how open the access is. The National Sporting Library in Middleburg VA is open to the public, the last time I checked.
The chart books also exist at Emerald Downs. However, one must have a spendy membership, and also say pretty please because they are not housed within the library proper.
There is a woman on the internet who used to be the editor of the American Racing Manual. She has an awesome library and used to promise answers to limited questions. But it seems that her enthusiasm for the sport has dampened, and my few contacts never resulted in much.
http://www.phalarisproject.com/archives.htm
Or visit my garage. I have a wall of them in heavy cardboard boxes, and not organized whatsoever. It might mean moving tons of books until getting to the ones you want.
There also are professional researchers who will do what you ask. They usually charge by the hour with a minimum that usually is 3 figures. I could steer you if you are interested.
Or let me know. I have helped people with a few answers by using online newspaper archives, rather than plowing through my mountain of chart books.