Just read it on the site. I am confused. I would have never thought that they would use something that light. It contradicts all other theories. As you know , I have a Winston Cup car. The motor was built by Mark Smith at Tristar who build for lots of Cup and Busch. I was told Unocal 20W50 or the equivalent in Pennzoil. If you are using an old tech solid lifter cam, the thin
oil might be a problem. Also, the tolerances your motor was built with should dictate the grade. I know drag racers have been using thin
oil for years and if Nascar can get more HP with thinner
oil, it might win a race. But they rebuild after every race and use fresh motors. I saw about the HP street car application but I am puzzled. I will talk to my engine builder and get back to you.