I've battled hot engines forever.  I don't think I've ever left a track under 220.  The average for me is 225-230.  I've tried every style of radiator.  I've put different restrictors, cap psi etc.  Tried a multitude of pumps and nothing really changed.  This week I changed the obvious.  The Pulley ratio.  I have been running a reduction since I started running as everyone thinks that's what works best.  I went from a 30 percent to 1-1 and I went from 230 - 170.  I thought my gauge was broke.  The motor got up to 200 on a long stretch but then actually cooled down on the yellow to 175.  The fan is really blowing air under yellows as well.  It has to do with how long the water is staying in the block.  I'm on a 3 pass radiator right now and it magnifies the issue of keeping the water in the block too long.  It was close to the same with a 2 pass.  I will never use anything but a 1-1 pulley on a 2-3 pass radiator again.  I came in the pits and usually that's when she really likes to heat up and instead cooled down.  I drove into my pits around 175.  I may need a smaller restrictor. Days of dumping water out of the motor are gone.

What kind of RPM's are you running?