I run VR-1 10W-30. 20W-50 is too high viscosity than needed or should be run in a street driven engine imo.
That is very dependent on locality and bearing clearances. Some current engines "demand" 5-20 because of their clearances.
Yes, agree. I know my statement was pretty generic. Years ago I remember running Castrol 20-50 racing oil in my Boss 302 thinking is must be better since its "racing oil". As I've learned more about oil flow, bearing clearances, etc., I've developed the opinion that extra high viscosity is not always better. Obviously, running 20-50 isn't going to destroy an engine, as far as I know, or even show apparent problems in most cases. Although, hard to know what, if anything, is happening since its hidden and could be gradual over time. For what its worth, the owners manuals only call for any multi-viscosity with 40 weight for temperatures above 90F. Similar to how much zinc is needed, its difficult to draw a hard line. End the end, probably ok for anyone to use whatever viscosity their experience and comfort level tells them.