Joe Gibbs website is contradictory jusl like the
oil debate. First it refers to clearances only the builder would know then it does an about face and uses horsepower and temperature for viscosity. Using that 95 percent of us should be using 5w20. I guess you pick and choose and in the in 99 percent of our cars Castro gtx with break-in additive would work. Avg price is $16 per quart, blah, blah