[Ed Wright]

For a tough heads up, mine is just a few hundredths quicker on Royal Purple "race 9", which is, IIRC, zero-10wt? Pours like water.

A friend in the lab at the Sunoco refinery here locally tested some oils for myself & a couple of racer/friends. The highest load before gaulding the ball on the load tester was 10W30 Valvoline VR1. I had used Penzoil for years, since they furnished my oil for a few years ago. When the free oil ended, I felt like I owed it to them to start buying it. Tested well also. The VR1 handled more load than anything. RP was very close. They tested what I could find. Pennzoil tested well too. VR1 tested best.
I am not claiming to know everything about this. Only what friends tested for us.
Your results may vary.