You don't want SUs. You want a Datsun factory setup with factory manifold, linkage, heat shield and twin Hitachi HJE38W carburetors. They are very similar to SUs.

* A12GX setup
* A12T setup

There is also an A14T setup which looks similar, but it is more complicated and has lower performance than the A12T/GX setups. It would be best for a stock (unmodified) A14 or A15.