Robert, you can always give AMSOIL's racing oil a try.
Dominator Racing oil
If you are interested let me know and we can work something out.
Maybe I should try that stuff for summer oil in my Blazer
It isn't recommended for street use due to the high content of ZDDP.
APPLICATIONS
AMSOIL Dominator Synthetic 15W-50 Racing Oil is recommended for high-rpm, high-horsepower, turbo/supercharged, gasoline- or alcohol-burning, nitro-fueled or nitrous oxide gas-injected applications operated under severe conditions.
Applications include, but are not limited to, the following:
• Asphalt Late Model • Dirt Late Model • Modified Big Block • Ford Crate Late Model • Dodge Crate Late Model • Endurance • Rally • Sprint • Truck-Pull • Aluminum Block • Marine • Other high-performance racing and street applications requiring 50-weight oil.