LS engine should be running the good old Mobil 1
synthetic 5w30
oil and while 150c is pushing the friendship the only damage will be that the
oil will oxidize quicker and it's life ill be shortened somewhat. It's a good idea to drop the
oil in a new engine after a couple of thousand anyway to get rid of the manufacture debris.
Synthetic oils oxidize much less than a mineral.
A mineral oil at that temperature would be just about stuffed and would require a change. A mineral oil's lie halves for each 10 degree rise above 70c. Automotive oils are packed with antioxidant additives and when exposed to high temps they soon get used up.
If your going to spank it on a track day I would change out to Mobil 1 5w50
Just my two cents but your engineer must be nuts doing a heavy track day to test the brakes before the full mechanical inspection.