The rear hubs are easy it is a direct swap you need to run the z31 cv's though. Good part is that apart from the hubs being a direct swap, so are the bearings, brake disk ( 88 vented) and calipers!! Get this NO fabbing!!
Note that because the Z31 stub axle is tapered, use the Z31 distance piece (bearing spacer) as the Z31 “B†spacer is the same length (55.95mm) as the ZX “M†spacer. If your 280ZX rear lower control arm housing needs the “N†length spacer (55.85mm) use the corresponding Z31 “A†spacer and if you require the “P†length spacer (56.05mm) use the corresponding Z31 “C†spacer.
This opens up a lot of possibilities for 280ZX applications as the Z31 stub axle came in three different varieties: a four-lug hub, a five-lug hub and a five-lug hub that used a vented rotor (which has a thicker wheel mounting flange). Utilizing either the turbo or the non-turbo Z31 companion flange you can use either the ZX CV axles (3 bearing joint) or the stronger Z31 turbo CV axles (with the 5 bearing joint).
Strange but I noticed that the diameter of the ZX stub axle is actually smaller (30mm vs. 32mm) than the first generation 1970-78 Z cars. The Z31 stub axle starts out at a 30mm diameter but then it tapers out to a diameter of 35mm where the wheel flange is. Nice upgrade.