If you are researching speed in American Foundation Arabians you might want to do a little research into the stallion Antez.
picture of Antez at Kellog
Antez would be a good place to start, when seeking information on American foundation Arabian horses with a propensity for racing/speed. Antez was purchased from the Kellogg Ranch by General J.M. Dickinson of the Travelers Rest Arabian Stud in Nashville, Tennessee. Dickinson was a breeder beginning in 1928. He purchased horses from previous "pioneer" breeders such as W.R. Brown's Maynesboro Stud in New Hampshire.
While Dickinson was not focusing on breeding racehorses per se, he was very interested in acquiring stock with superior athletic ability. He designed tests of endurance and speed for his horses, modeling his trials after the U.S. Army's endurance field tests from the 1920s. He also took Antez to a trotting track in Nashville to have him timed officially at shorter distances. Antez set a record (which I cannot recall off the top of my head), and an article about him appeared in a Polish horsemen's magazine in the 1930s. Eventually Antez was sold to breeders in Poland, where racing was used to test the athleticism, soundness, and temperament of stock there. Dickinson purchased several Polish Arabians (of racing pedigrees). These were the first Arabians to be imported to the U.S. (1937). Dickinson was a successful breeder, selling horses to owners in many states and foreign countries. His Arabians were as likely to work on ranches as become pleasure mounts. His bloodlines can be found in the earliest Arabian racers in the U.S. The first official race here took place in 1959. Dickinson's lines, along with those of the Polish Arabians imported as WII Prizes of War and other Kellogg horses, are well represented in the early years of the sport here.
I would like to direct you to a book I wrote that would elaborate on this exact topic. I do not know the rules about advertising on this forum, so please email me if you would like the title of the book. It is available online and not very expensive. Though its focus is on Tennesseans who have contributed to Arabian racing, my premise is that Arabian horse racing differs from Thoroughbred racing, firstly, due to the fact that the earliest runners were not bred specifically for running, but rather to be all-around, versatile riding horses. Unlike the centuries of breeding for speed among TBs, Arabian racehorses have a background in broader use, and among a broader ownership (not just the aristocracy that developed TB racing). This book developed out of my historical research for my Master's thesis dealing with class strata of horse ownership.
Dr. Sam Harrison, also of TN, elevated Arabian racing to the next level, as the sport made the transition from exhibition racing to pari-mutuel (where wagering is permitted). Of course, today, Arabians are bred solely for racing, but I think it is interesting that this has not compromised the conformation and utility of the breed, as one could argue halter classes have done.
If you are interested in the book, send me a private message, and I'll email you.