NZDatman
I don't know if an alloy carrier for the H165 was ever made.
H145,... yes H190,... yes, but H165? I plead ignorance, but should I ever stumble across one, I will tell you, & all of Datsun-dom.

2qk4u
If we are talking about the Datsun B120 ute rear axle setup, then the right disc brakes are the ones used on the Aussie 910 Bluebirds. [early to mid 80's] They were standard on the LX & TRX models, except for the very first of the series 1 LX models when supplies of components were not quite ready, & they got drums.

You will need to take the whole calliper complete with hose & the little bracket on the inner end of the hose that bolts to the axle housing.
Next, take the rotor [disc], then remove the whole rear axle shaft. The rest of the brake will come with it. You will need to remove the bearing from the axle so that you can salvage the brake parts.
Discard both bearing & axle, but make sure that you get the bolts & nuts that hold the brake plate to the axle housing as they are longer than the drum brake ones.

Next, strip the axle shafts from your ute axle housing & remove the bearings as before. Discard bearings & brakes.
If you can get a Bluebird workshop manual, it will show you how to assemble the new bearings to the axle after first sliding the disc brake's brake-plate on & reassembly is basicly the reverse of dissasembly, but read the manual as you go.
The brake hydraulics will need to duplicate the original bluebird setup & this will probably be the hardest part.

Before you slip the axles back in, have a think about the diff ratio. If you have the original 4.11 to 1 ratio from the ute, then remember that the donor car probably has a 3.9 to 1 differential in that old axle housing & this might be a better deal for use on the road with a souped up A series.

You will need 14" wheels to clear the brakes.
This design is a 'drum in disc' setup where the disc also has a small drum brake in it & this is the mechanical parking brake. The original ute hand brake cable looks like it will hook up ok, but since i have not done this yet, I can not guarantee that the handbrake linkage will fit, but I 'believe' it will.