A&Q about 350Z
Q:
I've just discovered that my 1990 Digi clyinder head is cracked. Is it possible to fit a Mk3 8v head to the 1.8 bottom end and would there be much of a power increase?
A:
No - you need to get a Mk2 one. The Mk3 head has no injector holes (they're in the manifold).
You should be able to find the right sort of head in the classifieds in here, or on a 1.8 passat (late 80s-early 90s model) in your local scrapper.