From some additional digging and consulting with the Nat’l Museum of Racing and HOF historian Allan Carter Bistnet did this “Rachel’s historic quest in perspective” article.
Among the findings …
Carter has found that Summer Guest is the only previous three-year-old filly who has competed in the Woodward, which was run for the first time in 1954.
Summer Guest, trained by J. Elliott Burch and ridden by Laffit Pincay, Jr. both members of the Hall of Fame, finished second to entrymate Key to the Mint in 1972, but was disqualified and placed third.
The only other fillies and mares who have competed in the Woodward are: Shuvee, who was fifth as a four-year-old in 1970 and sixth at the age of five in 1971; Relaxing, fourth at the age of five in 1981; and Lady’s Secret, second as a four-year-old during her Horse of the Year season in 1986.
Perhaps more importantly with perspective:
Furthermore, a victory in the Woodward would make Rachel Alexandra the first three-year-old filly to win a Grade 1 unrestricted route race on the dirt in New York since the system of grading races began in 1974.
Carter has reviewed the results of every major unrestricted Grade 1 dirt route race in New York and could confirm only one victory by a three-year-old filly, Lady Primrose in the 1887 Manhattan, then a 1 1/4-mile race on dirt. In addition to the Woodward and Manhattan, the races Carter examined were: the Jockey Club Gold Cup, the Whitney, the Suburban, the Metropolitan H. and the Brooklyn.