Looks like castrol changed the formulation of their Longlife-II oil, the new msds, dated July 6th, states that it is fully synthetic with no mineral oil, whereas the old msds specified mineral oil. Just a heads up for those interested.
Castrol sent me the following when I submitted a question to their "Ask the Expert" online
krholm.
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Castrol Syntec is a 100% fully-synthetic motor oil. Castrol SYNTEC is
not made with petroleum base stock. Synthetic motor oil starts with
synthetic base oil. There are many different chemical processes
available to make synthetic base oil due to advances in the technology
of synthetics. These chemical processes are different than the simple
refining techniques used to make conventional base oils...........................