Phar Lap

Factual error: In the shot of the start of the race at Agua Caliente - some of the horses in the line up are wearing ring head bridles (an Australian stock horse type bridle) - it would be unlikely that these American horses would be racing in such bridles.

Revealing mistake: During the last Race (the Agua Caliente), Phar Lap's hoof was re-opening from a crack earlier in the movie. When they show the close up of the leg/hoof during the race in slow motion, the "blood stain" keeps moving around on the leg wrap and hoof area.

Appyluver

Sub Editor: We have two versions ready to go. If he wins, "Australian wonder horse beats the world."
News writer: And if he loses?
Sub Editor: "New Zealand horse fails in Mexico."