I ran Wal-Mart special in all of my dirt motors.. Never had an oil related issue. Buddy running same class always used the highest dollar crap he could find. No discernable difference in bearings/wear on teardown.

I've used BP, VR1, Diesel oil (old stock "better" oil, additives, etc w A lowly 440 and burn cups and pushrods every 700 miles or so. Pretty !@$!$!$@ frustrating

Fwiw, best oil I've used is a special formulation a local shop had a semilocal refinery brew for them. Shop went out of business and I only have 2 gallons left.
The shop was building alot of USMTS mod motors. Oil seemed/seems like good stuff.