As mentioned, it is all about how your engine is setup. Old school loose clearances thick oil. One main reason for the loose clearances is a stock block was designed for what, 400HP and we build them to 700HP the block moves around during hard loads. Loose clearances absorb this deflection. I use 20W50 VR1 for years in my race car. Modern engine good stiff block tighter clearances 10W 30 or thinner. Almost all of my builds for street engines get 10w30 Lot of hydraulic roller lifters now will not work correctly with oil thicker than 10w30.

Maybe in blown alcohol or fuel, or an old shovelhead.

I run 5W-20 when index racing (B-Gas) and I run 0W when running N/A 10.5. I use Maxima Racing oils and have had awesome luck with it.

Goodness gracious that’s a beautiful car Are you on methanol or gas?

Gas

https://drivenracingoil.com/rt-5996-catalog.html

Download the catalog and find their chart on viscosity recommendations. I attached a photo as well. The section on viscosity recommendation also explains about running alcohol and how to choose a viscosity right for your engine.

I am not anywhere near as smart as they are but the best way to deal with fuel dilution on a E85 or Alky setup is #1 work on your tune so it doesn't milk the oil, #2 run the proper crankcase evacuation AKA a vac pump so what moisture is created is removed and #3 run your engine hot enough to help with evaporation of the moisture so the pump can remove it.

Nothing good ever comes from diluted oil.

I have been using 20W 50 and I believe that is why I am wearing down my bronze gear so quickly

I plan on switching to 10w30