From Handicapping Speed, pp. 81 - 82
copyright © 1991 Charles Carroll

Thoroughbred Time And Track Constants

The distance of the Thoroughbred flying start varies from track to track and, notably, from different distances on the same track. This was determined consciously--sometimes apparently semi-consciously--when the track was designed and built. It is well worth noting, if you are going to dissect racing times, how the starting gate is positioned in relation to the starting post at various distances at the tracks that you follow.

The Jockey Club rule (Part XIV, No. 149) is a little obscure on the issue: "the horses shall be started as far as possible in a line, but may be started at such reasonable distance behind the starting post as the starter thinks necessary...."