57 13/16 is the maximum dimension with halfshafts and spindles in a straght line. Any angle would reduce this dimension:
Rotor hat thickness= .28in
Spindle carrier u-joint center to spindle face= 7.75in
Halfshaft, ujoint c to c= 13 7/8in
Diff, ujoint cen to cen= 14 in
If you add all that up, you come up with 57 13/16