Here's what I got back from "Valvoline.com" when I asked them if Valvoline SynPower was made from group III base oils:

"Thank you for your message. Valvoline uses a mixture of various base oilsdesigned to provide the maximum performance for our SynPower line. All ofthe base fluids used in SynPower are synthetic. Some synthetic fluids are produced through a synthesis process that takesvery small molecules and assemble them into larger designer molecules withpremium lubricating properties. Others may be produced through a synthesisprocess that takes very large molecules, breaks them apart and re-arrangesthem to produce designer molecules with premium lubricating properties. Ineither case the end products are base fluids with extremely goodlubricating properties. However, all of them also carry with them certaininherent disadvantages. "