With the stock coolant thermostat of 190F, there have been discussions on this forum about what that means for transmission fluid temps. With water temps that high there is only so much the transmission cooler can do. I'm now seeing easily available, lower temp thermostats.
Even Autozone now offers 180F, 174F and 160F options for the L8T. 160F seems pretty low. But how low could you go without causing unintended problems?
Years ago when I was an engineer for a diesel engine manufacturer, our concerns with "too low" water temps was fuel dilution of the oil, excess soot generation, increased emissions from poor combustion. Other than soot generation, are they the same concerns with gas engines?
If you wanted to cool things off a bit, 180? or 174?, or .....?