Mine are the old San Antonio Zoo line, which were supposed to be known for being large and jet black. Didn't pair them up this year, but will next.
Don't hold out for me to produce any, lest Murphy strike, but the S.A.Z. line are known to be big. They are great snakes, require no supplemental heat, and are about as calm as cooked spaghetti (which eastern indigos are not always).