JRC,
My fan is always on unless the temp is under 70 degrees. I am running an aluminium radiator with two rows of 1 inch tubes and cross circulation (both my inlet and outlet are on the drivers side).
I am running an Edelbrock alum water pump with March pulleys.
I am also running a 50/50 mix of distilled water (not tap water) and anti-freeze with a one pint bottle of Water Weter. I am runnig a 190 degree Robert Shaw thermostat. Aluminium heads and manifold.
I think my biggest problem with my cooling was how poorly my original engine was built. Since Carbone's has built my engine I have not had any problems with heat or
oil pressure. I have made four or five races and ran everyday. After each event I would take my System One
oil filter apart and look for debris and so far I have found none. I have almost 2500 miles on this engine and I couldn't be happier with it.
EDIT-note. You MUST purge you engine of all air in your cooling system. I started my engine cool and barely looseded (cracked) the temp gauge sending unit and once the thermostat opened I let the air escape until it started pushing a little water out. Then I tightened it up again.
Clois