[Mike C]

Full floating means the axle shaft only drives the wheel and doesn't support the weight. It uses two wheel bearings on a hub like a front setup on a 4x4. You can spot these when the wheel centers are off by the protruding hub with 6 bolts in it.

The full float 14 came out in 1973 in GM trucks. The Semi-Float (meaning axles drive the wheel and support the weight, single wheel bearing in the housing like a car) came out in 1981. They are flat on the end except for where it chucks in the machine tools so no protrusion on the hub.

I would look for a 4.10 center section and run as tall a tire as possible in the near term as you budget for the OD trans. The 4.10 will be a better gear all around with the OD.