The early closed-knuckle front axles (Dana 25 from 1941-1959, Dana 27 from 1960-1971, and FSJ Dana 44s up to 1973) don’t hold up very well to 33-35s if a locker is used. Early Dana 25s had either a Bendix or Rzeppa joint until around 1950, when Spicer-style joints were used. Regardless of the joint style, all Dana 25 and Dana 27 have small 1.16-inch, 10-spline shafts. The Dana 27 has 10 bolts holding the ring gear to the carrier verses the Dana 25’s eight bolts and a slightly beefier centersection where the tubes press in. The open-knuckle Dana 30 was used in ’72-’86 Jeeps. Dana 30s run 1.16-inch shafts, but they’re of slightly better material and have stronger 27-spline inners.