I've a feeling my engine would not like 600F temperatures regardless of lube oil type.
After TWENTY YEARS untouched, a camshaft cover came off last week to replace an o-ring gasket. The cad plating on the inside of the cover looked like brand new oil had been smeared over a brand new cam cover.
The engine has 80,000 miles on it now.
For shame. 15 months and 5,600 miles it was discovered to be down exactly a quart. 5W-30 Castrol GTX.