Hi Bonemaro,
Most modern motor oils are dangerous to our air-cooled engines. The ZDDP additives that allow the lifter-to-cam contact surfaces to survive have been removed or diminished in them as pollutants.
Valvoline VR-1 racing oil (technically being a “racing” and not street oil) has a good amount of ZDDP in it. Also, as opposed to true racing oils, VR-1 has anti-rust additives in it that make it usable for street use where we keep oil in the engine for long periods of time. Specially formulated racing oils are drained between races.
You might suppose that all oil just by itself is rust preventative, but it actually takes some good additives to make that true.
I’m sure other posters here have oil suggestions. I’d use 10w30 or maybe 10w40 under really hot conditions.
FJC