A good rearend to use for 1/2 tons are the 60..66 or 67..7? truck rearends as they retain the 6 lugs and are only fractions of an inch wider and have a much broader range of available gear ratios.
I have a 69 rear with 3.08 posi and a 62 with a 3.73 posi - you will have to grind / torch off the trailing link suspension brackets and add spring perches - but E-Brake cable and brake line connections are pretty much identical.
