[Verdoro 68]

Originally Posted by Schurkey

For reasons of their own, Butler wants molasses in the oil pan. I think they're nuts.

Next time, try 5W-30. MAYBE 10W-30.

That's in line with Driven's viscosity recommendation based on my clearances.

https://drivenracingoil.com/c-138953...viscosity.html

I started using VR1 20w-50 years and years ago as a crutch for bad bearing clearances and the flat tappet I was running. I just kind of kept with the heavy stuff after the rebuild, especially since Butler recommended it. Seemed like a safe bet but then I started doing some research and thought maybe it's more than I need. There was a recent Engine Masters that tested viscosity that was pretty interesting.

Originally Posted by locomotivebreath

Are you using factory rally gauges ? I have repro rally’s and wonder how accurate they are but my psi with Mobil 15w50 seems about the same as yours .

Yes, factory rally gauges rebuilt and calibrated by Pete Serio so I trust them.