Just an FYI, T3 turbos can be had w/a T4 big shaft turbine wheels.
You can run a 76 MM compressor wheel on a T3 turbo if you would like.
I would run a intercooler.
Also, use an aluminum intake manifold. Preferably a Offy intake epspecially for a 230 CI engine.
You can run a 4bbl or 2 bbl carb w/the appropriate mods done to them.
To keep it simple, you can run a T3 turbo w/an internal wastegate.(no external wastegate plumbing to deal with)
Are you just adding a turbo to an existing stock cast piston engine? Or a purpose turbo built 230?
If you do not detonate, you could run 15 psi.
Not sure how much power you are looking to get?
MBHD
