I changed out the 440 source water pump to a mancini 6 blade with the anti-cavitation disc; reduced temps 15-20 degrees. I also use the hi-flow 160F thermostat. i'm still not where I want to be but was very surprised by a pump change.
I've also found that the stock blade-type waterpumps seem to flow/cool better than the newer style scroll type waterpumps.
Perhaps the scroll type impeller needs to be spun faster before it becomes more efficient.
I'm sure someone has done a study about that somewhere in the (recent) past.
