Here is a little tool you can use to see the differences between any four oils using the values on their data sheets
Viscosity Graph http://www.widman.biz/Seleccion/Viscosidad/Conversiones/Graph/graph.html

Thanks widman, this information is valuable.
Gracias boliviano.

I actually graphed a bunch of popular oils to see the ranges the protected engines in the writing of this new article.
Although I wrote it primarily for the Corvair, it has a lot of other interesting information.