Z18ET turbo, Z20, Z22. These crossflow-headed engines are based on the L-series. All install into a 1200 more or less the same way.
The nice thing about the Z18ET is its a factory setup, legal in most Australia states for a 1200. The downside is how available is it, including the wiring harness?
Swap Notes
Crossmember & Sump
Stock 1200 crossmember may be used unmodified:
Vanette Z-22 sump fits stock crossmember too: