from the care sheet on BP.net:

Hatchlings approximately 12 - 16"+/-. Females average 4'- 6', males average 3' - 5' adult size. Maximum size is around 10 feet, although 8'+ specimens are considered large. Blood pythons are heavy, robust snakes that may exceed 40 pounds in weight as mature adults.
anyone ever see a blood 8 foot or longer??