73-87 3/4 ton 14 bolt 10.5 ring gear full float or 9.5 ring gear semi float will bolt in and with a conversion ujoint.
Also thru 91 with a suburban 3/4 ton .
They both will be 8 lug.
The semi float can be converted to 6 lug with 88 and up 4x4 semi float axle shafts and spacing out the brakes.
88 and up axles will have a different spring perch spacing for the exception of the 3/4 ton suburban thru 91.
88 and up semi float axles can be either 6 or 8 lugs and come in 2 different widths, 4x2 65" wms or 68" wms approx.
again have diff spring perch spacing than the 73-87.