All 280zx's That's 1978 to 83 had power steering most also had AC. They are very common in the pick and pull yards and no one touches the steering stuff as it is not very usable in the 240's or 510's. The maxima's and 810 should have it and are also common. Some pickups, 610 and 710's will have it but good luck finding them with anything under the hood.
These will have a large alumanum braket on the drivers side of the block. This braket can hold both the power steering pump and AC compressor. These engines will have three row pullies to support this. The braket attaches to the side of teh block with 4 to 6 8mmX1.25 bolts typicaly 12mm head.
It will use these bosses on the block.
-Avery