In my experience, Subie engines run normally at about 178-183 degrees C.

When installing a Subaru into a Vanagon, I now use the Subaru single
wire (for dash)  temp sender and the B10 scan tool
http://www.graphics.cornell.edu/~v/b10scan/  with an old PC to
initially ensure the engine is running at proper temperature (the B10
software uses the Subaru two wire ECU temp sender).

Once the engine is consistently running around 180 degrees, I then
try different resisters (15-30 ohm usually) inline with the single
wire Subaru temp sender until the Vanagon dash temp gauge is right in
the middle (over the LED).

That's how I calibrate the dash gauge with a Subaru engine.

Note, the B10 scan tool is for 90-94 engines.  I don't think it works
on newer engines.

>
>As to David's issue, this is something that has long troubled me about
>the method used by many Subaru engine conversions to adjust the Subaru
>temp sender to the Vanagon dash gauge. Many do this with a resistor,
>selecting a resistor value that when put in series with the Subaru
>sender gives a temp gauge reading they are happy with on the Vanagon
>gauge under normal driving. How this combination of parts could be
>expected to give consistent readings at all engine temperatures is
>beyond me but I have not verified that it doesn't.
>
>The coolant level relay was modified during the 1985 model year to give
>improved behavior over the original version. There are 3 versions of
>this control unit, early, late, and latest. The first 2 versions have a
>"43" stamped on the top and the latest has a "42". All 3 have different
>part numbers on them as well. I have beat this horse to death many times
>here over the years so I will leave it at that.
>
>Mark