I also agree about the engine needing to break in a bit more, but also have a question.

Have you verified the your temperature guage is correct. It's not uncommon for a gauge to be off sometimes by a LOT. The easy way to check would be with one of the infrared temperatue guns. When checking the gauge I normally test 2 places, the thermostat housing where the coolant leaves the engine and directly on the sending unit where it screws into the engine.

My recently completed El Camino is a good example. I broke the cam in and got some run time on the engine in the shop with a known good mechanical temp gauge on it. When I hooked up the factory temp gauge it read a lot hotter so I checked with the IR temp gun. Turns out the factory setup reads 30 degrees hotter than the engine actually is.