if you are after an easier 5 speed then the L16 is a good engine
but fitment is better if you use an Na20e soch head which is the
evolution of the Z series heads which came after the L series.
The Na20 heads have roller rockers and like the Naps Z heads
sit 30-35mm lower than an L series head!

https://www.alibaba.com/product-detail ... 2017115.56.2677413fOMwMmP




they have beaut chambers and easily accept Z18et turbo manifolds
even exhaust accepts ka24e turbo manifold with little work.

Alloy rocker cover too you can source complete head from NZ for cheap
or Japan to get a complete head but I recommend the chinese heads as
they are new, used throughout Asia to replace the Jap porous units
and combustion chambers are more efficient than original Jap design.
Asian taxis use these heads and the efficient chamber design came
about as Asian taxi companies needed further fuel savings.

Another engine you can consider if you find one is the
Toyota 2tc or 3tc engines. OHV but big bores 1.6-1.8L
puerto ricans got just over 800hp from them as they
are what Datsun folk dream of in the AY heads.
Hemi chambers, crossflow and beautiful design with 5 speed box
from factory, alloy rocker cover and great aftermarket parts

http://automotorpad.com/toyota/274673-toyota-2tc-motor.html

2.2 litre version also possible using toyota 4Y crankshaft!