I believe 210 is about normal for a pushrod V8 engine. Just because your engine runs cooler with a lower stat doesn't mean that's benefiting the engine at all. Run it too cold and it will run rich. You want it to be in it's optimal operating temp for the best overall performance, efficiency, and wear. Your stock stat is fine...if anything, you can have the tuner adjust the fan to come on at a lower temp. But I wouldn't bother too much with it.
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