Dog:

http://www.carnut.com/specs/rear.html

http://www.hemmings.com/partslocator/axles.html

et cetera

Not sure what you mean by "direct swap". The 53 orginally has torque-tube so any open hotchkiss type leaf spring rear is not "direct". The table like listed above give you your rear end widths, which is the primary fitment measure, which looks like you have considered.

You still may need to move the position of the spring perches (cut and weld new ones on), giving consideration for the pinion (driveline) angles and the side to side position.

Then you have driveshaft length and U-joint connection to work out.

Finally the nit stuff like emergency brake cables and brake line connection.

Last edited by R-Bo; 01/09/2014 4:46 PM.

R-Bo

1959 Apache 1/2 ton Big Window, Short bed Fleetside (under reconstruction)
1966 GMC 305V6 in the family