Coming into this very late, so just some random thoughts. I own a 2011 Corvette that I track as often as possible.
It's not unusual for an accomplished driver on even a warm summer day to drive oil temperatures to 300 degrees in a 20 minute session in a C6 without additional cooling. When you roll into the pits and the oil is still that hot, oil pressures were be in the lower single digits, so it's been long known that a higher viscosity oil is necessary for engine protection during serious track work, despite what the owner's manual may have said back then.
Also, an engine is only around 25% thermodynamically efficient (though some modern gasoline engines are approaching 35% or maybe a bit higher), so 75% of the energy produced by burning gasoline goes into heat. While the LS3 is 6.2 liters, the overall physical size and mass of the engine is very low in comparison to an overhead cam engine. The LS3 occupies a small physical volume than a BMW 4.4 liter V8, for instance, though it makes considerably more power. So the heat production per unit volume is greater in the LS3 than in many other motors. And the lightness means it is a smaller heat sink, and that lightness also means it also works as a transplant into a small vehicle like a Miata.
Lastly, I've run HPDE's in both the dry and the wet at about the same air temperatures. While there are obviously differences in cooling in wet and dry environments, I typically run about the same RPMs in both instances, but also a gear lower in the wet. In the wet, though, I usually can't get anywhere near full throttle, and consequently oil temperatures never get that hot, maybe 240-245 F. In the dry at the same ambient temperature, I can get the oil temps up to about 280 F. This is also despite higher speeds and thus greater airflow through the various coolers in the dry. So my experience (and that of those who do HPDE sessions) is that full throttle use generates a lot more heat than simply running at similarly high RPMs but at lower throttle openings.
