This is the brand of oil I run. It is very good oil, but not available in the US as far as I am aware. But you will note that they recommend 20w60 for 3.5 V8s, 15w/60 for the 3.9's and 10w50 for the 4.0's and 4.6's. I run the 15w60 only because of its high temp viscosity of 60W, otherwise I would run a 20w50 if I had nothing else available. But most places I can get a high temp viscosity of 50W or above without going above 15W on the cold temp rating. I am not too concerned about the cold viscosity as I do not live in a cold climate. But if you guys live in an area that snows, etc, the bottom viscosity becomes more important. But I run my Rangie in 40C temperatures and often at high revs under extreme loads. But as stated previously, you pick the oil that best suits what YOU do and don't listen to people who claim to be experts.
Penrite Oil
