I just built a stroker RB for my Dart, and it has 11-1 compression, RPM heads, mild cam (with lot's of duration), MSD ignition, etc.

It has a 440 source alum water pump package, a Zirgo 16" fan (supposed to flow upwards of 3000 cfm ), and a Northern 26 aluminum rad. It currently has a 160* thermostat.

It only has about 30 miles on the whole thing (da#m snow ).

It too will run up to 210 or so idling in traffic, and come down 10-15* once moving again.

I was told that a newly built engine will run hot, until it loosens up a little. I have no idea if this is true or not. Maybe someone here will chime in.

I have also been told by a competent builder here that 210* is nothing to worry about. Personally I'd be happier if it ran at 180-190*.

I'm gonna change my thermostat to a 180 0r 195, to see if that will make a difference, as it should keep the coolant in the rad longer.

What thermostat do you have in there?

codfish